Biomarkers useful for diagnosing prostate cancer, and methods thereof

ABSTRACT

The present invention describes a method for predicting a health-state indicative of the presence of prostate cancer. The method measures the intensities of specific small biochemicals, called metabolites, in a blood sample from a patient with an undetermined health-state, and compares these intensities to the intensities observed in a population of healthy individuals and/or to the intensities previously observed in a population of confirmed prostate cancer-positive individuals. The method enables a practitioner to determine the probability that a screened patient is positive for prostate cancer.

This application is a continuation of U.S. patent application Ser. No. 12/294,215, which is a national stage application under 35 U.S.C. §371 of PCT/CA2007/000469, filed Mar. 23, 2007, which claims the priority benefit of U.S. Provisional Application No. 60/785,480, filed Mar. 24, 2006.

FIELD OF THE INVENTION

The present invention relates to small molecules or metabolites that are found to have significantly different abundances or intensities between clinically diagnosed prostate cancer-positive patients and normal patients. The present invention also relates to methods for diagnosing prostate cancer, or the risk of developing prostate cancer.

BACKGROUND OF THE INVENTION

Prostate cancer will affect one in every six men during their lifetime, with over 200,000 diagnoses and 30,000 deaths per year in the U.S. alone (1). It is the second leading cause of death due to cancer in men. Current screening methods for prostate cancer include the prostate-specific antigen (PSA) test, which detects the levels of prostate-specific antigen in a blood sample, and digital rectal examination (DRE). Although 60 to 70% of at-risk men in the U.S. have undergone PSA testing since the test was adopted, prostate cancer death rates have only slightly decreased. This is largely due to two reasons: 1) the fact that PSA testing fails to identify a subset of aggressive cancers, and 2) that only about 30% of men with a positive PSA test have a positive biopsy. Diagnosis is further complicated by the fact that of all men treated for prostate cancer, about 25% have disease recurrence and require additional treatment, while in other cases some tumors never progress at all and may be better left untreated. Therefore, a key issue with prostate cancer diagnosis today is the inability to predict the course of the disease. Together, these statistics have made prostate screening with conventional methods a controversial issue. The ideal prostate cancer biomarker(s) would therefore be suitable for early detection, as well as have the ability to predict disease aggressiveness and ideally to be able to monitor disease progression during therapy or post surgery.

Currently, PSA is recognized as the best available serum marker for prostate cancer, however, there is substantial room for improvement. The impact of PSA testing, beginning in the early 1990s, can be seen by decreases in the numbers of men diagnosed with metastasis, concurrent with overall decreased mortality (2). However, this may be due to the fact that PSA screening increased awareness of prostate cancer, which ultimately stimulated the analysis of more biopsies. Calculating the performance characteristics (sensitivity and specificity) of the PSA test is difficult because of ethnicity-related difference in incidence, and that in most studies, the percentage of biopsies performed is higher than what would normally be performed in clinical practice. In the Prostate Cancer Prevention Trial (PCPT) (3), the false-negative rate for detection of high-grade tumors was at least 15%, with a false-positive rate of 70% (i.e. only 30% of men with elevated PSA have a positive biopsy). In another study, the Physician's Health Study (4), the sensitivity for aggressive cancer over a four-year period was 87%, but dropped to 53% for non-aggressive cancers. There have been many other studies carried out to assess PSA sensitivity, but the latest findings claim overall sensitivity to be at best 73% (5). Lowering the PSA threshold would detect more cancers, but at the cost of more false-positives and subsequently more biopsies. To complicate matters further, it appears that due to increased prevalence of benign prostatic hyperplasia (BPH) in the ageing male population, the sensitivity of the PSA test with a cut-point of 4 ng/ml decreases with age.

PSA alone cannot diagnose prostate cancer. Diagnosis is a complex process, which involves integrating the results of a physical examination, a PSA test, the Gleason grade (by assessing glandular architecture at biopsy) and possibly other lab tests.

It is clear that there is a need for improving prostate cancer detection. A test that is able to detect risk for, or the presence of, prostate cancer or that can predict aggressive disease with high specificity and sensitivity would be very beneficial and would impact prostate cancer morbidity. The claimed invention describes the discovery of molecules present in serum samples which show a differential pattern of abundances between prostate cancer patients and normal individuals.

SUMMARY OF THE INVENTION

The present invention relates to small molecules or metabolites that are found to have significantly different abundances or intensities between clinically diagnosed prostate cancer-positive patients and normal patients. The present invention also relates to methods for diagnosing prostate cancer, or the risk of developing prostate cancer.

The present invention provides a method for identifying, validating, and implementing a high-throughput screening (HTS) assay for the diagnosis of a health-state indicative of prostate cancer. In a particular example, the method encompasses the analysis of prostate cancer-specific and normal biological samples using non-targeted FTMS technology to identify all statistically significant metabolite features which differ between normal and prostate cancer-positive biological samples, followed by the selection of the optimal feature subset using statistics and chemical properties of the molecules, and characterization of the feature set using methods including, but not limited to, chromatographic separation, mass spectrometry (MS/MS), and nuclear magnetic resonance (NMR), for the purposes of:

-   -   1. separating and identifying retention times of the         metabolites;     -   2. producing descriptive MS/MS fragmentation patterns specific         for each metabolite;     -   3. characterization of molecular structures; and     -   4. developing a high-throughput quantitative or         semi-quantitative MS/MS-based diagnostic assay.

The present invention further provides a method for the diagnosis of prostate cancer or the risk of developing prostate cancer in humans by measuring the levels of specific small molecules present in a sample and comparing them to “normal” reference levels. The methods measure the intensities of specific small molecules, also referred to as metabolites, in the sample from the patient and compare these intensities to the intensities observed in a population of healthy individuals.

The present invention provides a method of identifying one or more than one metabolite marker for diagnosing prostate cancer, comprising the steps of:

-   -   a) introducing one or more than one sample from one or more than         one patient with prostate cancer, said sample containing a         plurality of metabolites into a high resolution mass         spectrometer     -   b) obtaining quantifying data for the metabolites;     -   c) creating a database of said quantifying data;     -   d) comparing the identifying and quantifying data from the         sample with corresponding data from a sample from one or more         than one reference sample; and     -   e) identifying one or more than one metabolite marker that         differs between said sample and said one or more than one         reference sample.

The metabolite markers are selected from the metabolites listed in Table 1, or any combination thereof. The method may further comprise selecting a minimal number of metabolite markers needed for optimal diagnosis. The high resolution mass spectrometer may be a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTMS).

The present invention also provides a method for diagnosing prostate cancer or the risk of prostate cancer in a patient, the method comprising the steps of:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifiying data for one or         more than one metabolite marker;     -   c) comparing the quantifying data for said one or more than one         metabolite marker to corresponding data obtained from one or         more than one reference sample; and     -   d) using said comparison to differentially diagnose prostate         cancer or the risk of prostate cancer.

The one or more than one metabolite marker is selected from the metabolites listed in Table 1, or any combination thereof. The diagnostic method above may comprise analyzing the sample by liquid chromatography mass spectrometry (LC-MS) in step b). Alternatively, when the method is a highthroughput method, step b) may comprise analyzing the sample by either liquid chromatography or direct injection followed by linear ion trap tandem mass spectrometry.

In the method as described above, the one or more than one reference sample may be a plurality of samples obtained from control individuals; one or more than one baseline sample obtained from the patient at an earlier date; or a combination thereof.

In another embodiment of the present invention, there is provided a method for diagnosing prostate cancer or the risk of prostate cancer in a patient, the method comprising the steps of:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifiying data for one or         more than one metabolite marker;     -   c) obtaining a ratio for each of the one or more than one         metabolite marker to an internal control metabolite;     -   d) comparing each ratio of said one or more than one metabolite         marker to the internal control metabolite to corresponding data         obtained from one or more than one reference sample; and     -   e) using said comparison to diagnose prostate cancer or the risk         of prostate cancer.

The diagnostic method above may comprise one or more than one metabolite marker selected from metabolites listed in Table 1, or any combination thereof. The diagnostic method above may comprise analyzing the sample by liquid chromatography mass spectrometry (LC-MS) in step b). Alternatively, when the method is a highthroughput method, step b) may comprise analyzing the sample by either direct injection or liquid chromatography and linear ion trap tandem mass spectrometry.

In the method as described above, the one or more than one reference sample may be a plurality of samples obtained from control individuals; one or more than one baseline sample obtained from the patient at an earlier date; or a combination thereof.

The present invention further provides a method for evaluating the efficacy of a therapy for treating prostate cancer in a patient, comprising:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifying data for one or         more than one metabolite marker;     -   c) comparing said quantifying data to corresponding data         obtained from one or more than one reference sample; and     -   d) using said comparison to determine whether the therapy is         improving the health state of the patient,         wherein the one or more than one metabolite marker is selected         from metabolites listed in Table 1, or any combination thereof.         The diagnostic method above may comprise analyzing the sample by         liquid chromatography mass spectrometry (LC-MS) in step b).         Alternatively, when the method is a highthroughput method,         step b) may comprise analyzing the sample by direct injection or         liquid chromatography and linear ion trap tandem mass         spectrometry.

In the method as described above, the one or more than one reference sample may be a plurality of samples obtained from control individuals; one or more than one pre-therapy baseline sample obtained from the patient; or a combination thereof.

In yet another embodiment of the present invention, there is provided a method for evaluating the efficacy of a therapy for treating prostate cancer in a patient, comprising:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifying data for one or         more than one metabolite marker;     -   c) obtaining a ratio for each of the one or more than one         metabolite marker to an internal control metabolite;     -   d) comparing each ratio of said one or more than one metabolite         marker to the internal control metabolite to corresponding data         obtained from one or more than one reference sample; and     -   e) using said comparison to determine whether the therapy is         improving the health state of the patient,         wherein the one or more than one metabolite marker is selected         from metabolites listed in Table 1, or any combination thereof.         The diagnostic method above may comprise analyzing the sample by         liquid chromatography mass spectrometry (LC-MS) in step b).         Alternatively, when the method is a highthroughput method,         step b) may comprise analyzing the sample by direct injection or         liquid chromatography and linear ion trap tandem mass         spectrometry.

In the method as described above, the one or more than one reference sample may be a plurality of samples obtained from control individuals; one or more than one pre-therapy baseline sample obtained from the patient; or a combination thereof.

The methods described herein may be combined with other methods for monitoring prostate cancer, for example the PSA test.

In the diagnostic methods and methods of evaluating the efficacy of treatment as described above, the one or more than one metabolite marker may be selected from the group consisting of lysophospholipids, including lysophosphatidylcholines, lysophosphatidylethanolamines, lysophosphatidyldimethylethanolamines, lysophos-phatidylserines, lysosphingosylphosphorylcholines, lysophosphatidylglycerols lysophosphatidylinositols, platelet activating factors (PAFs), and combinations thereof. For example, the one or more than one metabolite marker may comprise metabolites with accurate masses measured in Daltons of, or substantially equivalent to, a) 495.3328, b) 517.3148, c) 519.3328, d) 521.3480, e) 523.3640, f) 541.3148, g) 545.3460, h) 481.3171, i) 531.3123, j) 541.3422, k) 555.3101, l) 565.3394, m) 567.3546, and n) 569.3687. In methods where the quantifying data for the one or more than one metabolite is compared, these metabolites are observed to be decreased in patients with prostate cancer. In methods where a ratio for the one or more than one metabolite to the internal control metabolite is compared, the ratio of metabolite to internal control metabolite is decreased in patients with prostate cancer.

The metabolites a) to g) are lysophosphatidylcholine-related compounds and metabolites h) to n) are putatively N,N-dimethyl lysophosphatidylethanolamine-related compounds. Metabolites a) to n) may be further characterized by an MS/MS spectrum as shown in a) FIG. 7, and/or as described in Table 3; b) FIG. 8, and/or as described in Table 4; c) FIG. 9, and/or as described in Table 5; d) FIG. 10, and/or as described in Table 6; e) FIG. 11, and/or as described in Table 7; f) FIG. 12, and/or as described in Table 8; g) FIG. 13, and/or as described in Table 9; h) FIG. 14, and/or as described in Table 12; i) FIG. 15, and/or as described in Table 13; j) FIG. 16, and/or as described in Table 14; k) FIG. 17, and/or as described in Table 15; l) FIG. 18, and/or as described in Table 16; m) FIG. 19, and/or as described in Table 17; and n) FIG. 20, and/or as described in Table 18, respectively.

Additionally, the one or more than one metabolite above may be further characterized by molecular formula a) C₂₄H₅₀NO₇P, b)C₂₆F₁₄₈NO₇P, c) C₂₆H₅₀NO₇P, d) C₂₆H₅₂NO₇P, e) C₂₆H₅₄NO₇P, f) C₂₈H₄₈NO₇P, g) C₂₈H₅₂NO₇P, h) C₂₃H₄₈NO₇P, i) C₃₀H₄₆NO₅P, j) C₂₅H₅₂NO₉P, k) C₂₅H₅₀NO₁₀P, l) C₂₇H₅₂NO₉P, m) C₂₇H₅₄NO₉P, and n) C₂₇H₅₆NO₉P, respectively. The structures of the one or more than one metabolite may be characterized as follows:

respectively.

The present invention also provides novel compounds. These compounds are selected from the group consisting of the metabolites with accurate masses measured in Daltons of, or substantially equivalent to, a) 531.3123, b) 541.3422, c) 555.3101, d) 565.3394, e) 567.3546, and f) 569.3687.

The compounds described above may be further characterized by an MS/MS spectrum as shown in

-   -   a) FIG. 15, and/or as described in Table 13;     -   b) FIG. 16, and/or as described in Table 14;     -   c) FIG. 17, and/or as described in Table 15;     -   d) FIG. 18, and/or as described in Table 16;     -   e) FIG. 19, and/or as described in Table 17; and     -   f) FIG. 20, and/or as described in Table 18, respectively.

Likewise the compounds described above may be further characterized by an MS/MS spectrum as shown in tables 12 through 18, respectively.

The compounds may also be further characterized by molecular formula a) C₃₀H₄₆NO₅P, b) C₂₅H₅₂NO₉P, c) C₂₅H₅₀NO₁₀P, d) C₂₇H₅₂NO₉P, e) C₂₇H₅₄NO₉P, and f) C₂₇H₅₆NO₉P, respectively. In addition, the compounds described above may be characterized by the putative structures

respectively.

The novel compounds of the present invention may be used for the diagnosis of prostate cancer, or for evaluating the efficacy of treatment of prostate cancer in a patient.

The present invention may significantly impact the ability to detect prostate cancer or the risk of developing prostate cancer, and may save lives. The statistical performance of a test based on these samples suggests that the test will outperform the PSA test, the only other serum-based diagnostic test for prostate cancer. Alternatively, a combination of the methods described herein and the PSA test may improve the overall diagnostic performance of each test.

The methods of the present invention, including HTS assays, can be used for the following, wherein the specific “health-state” refers to, but is not limited to prostate cancer:

1. identifying small-molecule metabolite biomarkers which can discriminate between prostate cancer-positive and prostate cancer-negative individuals using any biological sample, such as a serum sample, taken from the individual;

2. specifically diagnosing prostate cancer using metabolites identified in a sample such as serum, plasma, whole blood, and/or other tissue biopsy as described herein;

3. selecting the minimal number of metabolite features required for optimal diagnostic assay performance statistics using uni- or multivariate statistical methods and relevant chemical information about the molecules such as those mentioned herein;

4. identifying structural characteristics of biomarker metabolites selected from non-targeted metabolomic analysis using LC-MS/MS, MS^(n) and NMR;

5. developing a high-throughput triple-quadrupole MS/MS method for assaying selected metabolite levels in a sample;

6. diagnosing prostate cancer, or the risk of developing prostate cancer, by determining the levels of any combination of metabolite features disclosed from the FTMS analysis of patient sample, using any method including but not limited to mass spectrometry, NMR, UV detection, ELISA (enzyme-linked immunosorbant assay), chemical reaction, image analysis, or other;

7. monitoring any therapeutic treatment of prostate cancer, including drug (chemotherapy), radiation therapy, surgery, dietary, lifestyle effects or other; and/or

9. longitudinal monitoring or screening of the general population for prostate cancer using any single or combination of features disclosed in the method.

The impact of the present invention on the diagnosis of prostate cancer would be tremendous, as literally everyone could be screened longitudinally throughout their lifetime to assess risk. Given that the performance characteristics of the test of the present invention are representative for the general population, this test alone may be superior to any other currently available screening method, as it may have the potential to detect disease progression prior to the emergence of clinical symptoms.

This summary of the invention does not necessarily describe all features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings wherein:

FIG. 1 shows a summary of the steps involved in the discovery, identification and characterization of metabolites, including those relating to lysophospholipid species, which are associated with the presence of prostate cancer.

FIG. 2 shows a principle component analysis (PCA) plot generated from the 492 masses with p-values less than 0.05. Each point on the plot represents a single patient sample, while the dotted line represents the boundary between which most of the prostate cancer subjects (in black) and the controls (grey), can be separated.

FIG. 3 shows a PCA plot generated from a subset of 14 masses selected from the 492 with p-values <0.05. A high degree of discrimination between the prostate cancer subjects (black points) and the control subjects (grey points) is evident using only the 14 masses. The dotted line shows the boundary between the two cohorts, which when used as a cutoff value results in 84% sensitivity (84% of cancers detected) and 100% specificity (no controls being classified as cancer, or false positives).

FIG. 4 shows a bar graph of the average relative intensities of the 14 selected masses in the control (grey) and the prostate cancer subjects (black). Error bars=±1s.d.

FIG. 5 shows a series of extracted mass spectra for metabolites eluting between 16 and 18 minutes of chromatographic separation on HPLC, as detected using time-of-flight (TOF) MS. The box indicates a region of metabolite masses detected between approximately 450 and 600 daltons in control serum (A), but absent from prostate cancer-positive serum (B). The lower panel (C) indicates the net difference between the control and prostate cancer spectra.

FIG. 6 shows a graph of the 14 said metabolites as detected using TOF-MS following HPLC. Error bars=±1s.d.

FIG. 7 shows the MS/MS extracted mass spectra for 495.3328 (496.3401 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 8 shows the MS/MS extracted mass spectra for 517.3148 (518.3219 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 9 shows the MS/MS extracted mass spectra for 519.3328 (520.3401 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 10 shows the MS/MS extracted mass spectra for 521.3480 (522.3554 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 11 shows the MS/MS extracted mass spectra for 523.3640 (524.3713 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 12 shows the MS/MS extracted mass spectra for 541.3148 (542.3219 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 13 shows the MS/MS extracted mass spectra for 545.3460 (546.3534 [M+H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 14 shows the MS/MS extracted mass spectra for 481.3171 (480.3091 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 15 shows the MS/MS extracted mass spectra for 531.3123 (530.3035 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 16 shows the MS/MS extracted mass spectra for 541.3422 (540.3335 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 17 shows the MS/MS extracted mass spectra for 555.3101 (554.3013 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 18 shows the MS/MS extracted mass spectra for 565.3394 (564.3306 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 19 shows the MS/MS extracted mass spectra for 567.3546 (566.3459 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 20 shows the MS/MS extracted mass spectra for 569.3687 (568.3598 [M−H]), at collision energy voltages of 20 (A), 35 (B) and 50 (C) volts, respectively.

FIG. 21 shows A), the list of the parent-daughter ion transitions used for the positive ESI triple-quadrupole HTS method as well as the R-squared correlation coefficient resulting from calculation of linearity across five diluted samples. B), Standard curve for transition 496.3/184.2a1. C). The average ratio (biomarker:IS peak area) for each transtion in the prostate (black) and control (grey) subjects.

FIG. 22 shows A), a scatter plot of the positive ESI HTS patient scores for 147 male controls (grey squeares) and 24 prostate cancer patients (black triangles). B), frequency histogram showing the distribution of the control population (grey) and prostate cancer subjects (black) according to binned patient scores.

FIG. 23 shows A), the list of the parent-daughter ion transitions used for the negative ESI triple-quadrupole HTS method as well as the R-squared correlation coefficient resulting from calculation of linearity across five diluted samples. B), Standard curve for transition 480.3/255.4a1. C). The average ratio (biomarker:IS peak area) for each transtion in the prostate (black) and control (grey) subjects.

FIG. 24 shows A), a scatter plot of the negative ESI HTS patient scores for 147 male controls (grey squeares) and 24 prostate cancer patients (black triangles). B), frequency histogram showing the distribution of the control population (grey) and prostate cancer subjects (black) according to binned patient scores.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to small molecules or metabolites that are found to have significantly different abundances or intensities between clinically diagnosed prostate cancer-positive patients and normal patients. The present invention also relates to methods for diagnosing prostate cancer, or the risk of developing prostate cancer.

The present invention provides novel methods for discovering, validating, and implementing a diagnosis method for prostate cancer. In one embodiment of the present invention, there is provided a method for identifying specific biomarkers for diagnosing prostate cancer comprising the steps of: introducing one or more than one sample from one or more than one patient with prostate cancer, said sample containing a plurality of metabolites into a high resolution mass spectrometer (for example, and without wishing to be limiting, a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTMS)); obtaining, identifying and quantifying data for the metabolites; creating a database of said quantifying data; comparing the quantifying data from the sample with corresponding data obtained from one or more than one sample from a control patient; identifying one or more than one metabolites that differ. The metabolite markers identified using the method of the present invention may include the metabolites listed in Table 1. The method may further comprise selecting the minimal number of metabolite markers needed for optimal diagnosis.

In order to determine the biochemical markers of a given health-state in a particular population, a group of patients representative of the health state (i.e., a particular disease) and/or a group of “normal” or “control” counterparts (i.e., individuals that do not suffer from the particular health state) are required. Biological samples taken from the patients in the particular health state can then be compared to the same samples taken from the normal population as well as to patients in similar health-state category in the hopes of identifying biochemical differences between the two groups, by analyzing the biochemicals present in the samples using analytical methods including, but not limited to, FTMS and/or LC-MS.

The method for the discovery of metabolite markers as described above may be done using non-targeted metabolomic strategies or methods. Multiple non-targeted metabolomics strategies have been described in the scientific literature including NMR (6), GC-MS (7), LC-MS (8), and FTMS strategies (9-11). The metabolic profiling strategy employed for the discovery of differentially expressed metabolites in the present invention was the non-targeted FTMS strategy by Phenomenome Discoveries [21, 24-27; see also US Published Application No. 2004-0029120 A1, Canadian Application No. 2,298,181, and WO 0157518]. Non-targeted analysis involves the measurement of as many molecules in a sample as possible, without any prior knowledge or selection of components prior to the analysis. Therefore, the potential for non-targeted analysis to discover novel metabolite biomarkers is high versus targeted methods, which detect a predefined list of molecules. The present invention uses a non-targeted method to identify metabolite components in serum samples that differ between individuals with prostate cancer and control individuals (i.e., individuals that do not have prostate cancer).

However, a person skilled in the art would recognize that other metabolite profiling strategies could be used to discover some or all of the differentially regulated metabolites disclosed in the present invention and that the metabolites described herein, however discovered or measured, represent unique chemical entities that are independent of the analytical technology that may be used to detect and measure them. For example, and without wishing to be limiting in any manner, other methods of metabolite detection could be used, for example other MS-based platforms, ELISAs, colorimetric assays, etc.

The present invention also provides a method for diagnosing prostate cancer or the risk of developing prostate cancer in a patient, the method comprising the steps of:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifiying data for one or         more than one metabolite marker;     -   c) comparing the quantifying data for said one or more than one         metabolite marker to corresponding data obtained from one or         more than one reference sample; and     -   d) using said comparison to diagnose prostate cancer or the risk         of developing prostate cancer.

The step of analyzing the sample (step b) may comprise analyzing the sample using a mass spectrometer (MS). For example, and without wishing to be limiting, such mass spectrometer could be of the FTMS, orbitrap, time-of-flight (TOF) or quadrupole types. Alternatively, the mass spectrometer could be equipped with an additional pre-detector mass filter. For example, and without wishing to be limiting such instruments are commonly referred to as quadrupole-FTMS (Q-FTMS), quadrupole-TOF (Q-TOF) or triple quadrupole (TQ or QQQ). In addition, the mass spectrometer could be operated in either the parent ion detection mode (MS) or in MSn mode, where n>=2. MSn refers to the situation where the parent ion is fragmented by collision induced dissociation (CID) or other fragmentation procedures to create fragment ions, and then one or more than one of said fragments are detected by the mass spectrometer. Such fragments can then be further fragmented to create further fragments. Alternatively, the sample could be introduced into the mass spectrometer using a liquid or gas chromatographic system or by direct injection.

In the methods of the present invention, any type of biological sample that originates from anywhere within the body, for example but not limited to, blood (serum/plasma), CSF, urine, stool, breath, saliva, or biopsy of any solid tissue including tumor, adjacent normal, smooth and skeletal muscle, adipose tissue, liver, skin, hair, brain, kidney, pancreas, lung, colon, stomach, or other may be used. Of particular interest are samples that are serum. While the term “serum” is used herein, those skilled in the art will recognize that plasma or whole blood or a sub-fraction of whole blood may also be used.

The biological samples may be obtained in both normal and prostate cancer-positive groups from a diverse population of individuals, ranging in age, ethnicity, weight, occupation, and displaying varying non-prostate cancer-related health-states. Choosing subjects in this way introduces more variability into a dataset, however, reduces potential confounding bias that ultimately results in a more robust set of biomarkers (since it can still detect disease in the presence of many other variables).

In a non-limiting example, when a blood sample is drawn from a patient there are several ways in which the sample can be processed. The range of processing can be as little as none (i.e. frozen whole blood) or as complex as the isolation of a particular cell type. The most common and routine procedures involve the preparation of either serum or plasma from whole blood. All blood sample processing methods, including spotting of blood samples onto solid-phase supports, such as filter paper or other immobile materials, are also contemplated by the present invention.

Without wishing to be limiting in any manner, the processed blood or serum or sample described above may then be further processed to make it compatible with the methodical analysis technique to be employed in the detection and measurement of the metabolites contained within the processed serum or blood sample. The types of processing can range from as little as no further processing to as complex as differential extraction and chemical derivatization. Extraction methods could include sonication, soxhlet extraction, microwave assisted extraction (MAE), supercritical fluid extraction (SFE), accelerated solvent extraction (ASE), pressurized liquid extraction (PLE), pressurized hot water extraction (PHWE) and/or surfactant assisted extraction (PHWE) in common solvents such as methanol, ethanol, mixtures of alcohols and water, or organic solvents such as ethyl acetate or hexane. A method of particular interest for extracting metabolites for FTMS non-targeted analysis as well as for direct injection on triple quadrupole mass spectrometers, is to perform a liquid/liquid extraction whereby non-polar metabolites dissolve in an organic solvent and polar metabolites dissolve in an aqueous solvent.

The extracted samples may be analyzed using any suitable method known in the art. For example, and without wishing to be limiting in any manner, extracts of biological samples are amenable to analysis on essentially any mass spectrometry platform, either by direct injection or following chromatographic separation. Typical mass spectrometers are comprised of a source which ionizes molecules within the sample, and a detector for detecting the ionized molecules or fragments of molecules. Non-limiting examples of common sources include electron impact, electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), atmospheric pressure photo ionization (APPI), matrix assisted laser desorption ionization (MALDI), surface enhanced laser desorption ionization (SELDI), and derivations thereof. Common mass separation and detection systems can include quadrupole, quadrupole ion trap, linear ion trap, time-of-flight (TOF), magnetic sector, ion cyclotron (FTMS), Orbitrap, and derivations and combinations thereof. The advantage of FTMS over other MS-based platforms is its high resolving capability that allows for the separation of metabolites differing by only hundredths of a Dalton, many which would be missed by lower resolution instruments.

By the term “metabolite”, it is meant specific small molecules, the levels or intensities of which are measured in a sample, and that may be used as markers to diagnose a disease state. These small molecules may also be referred to herein as “metabolite marker”, “metabolite component”, “biomarker”, “biochemical marker”, or “metabolite feature”.

The metabolites are generally characterized by their accurate mass, as measured by mass spectrometry technique used in the above method. The accurate mass may also be referred to as “accurate neutral mass” or “neutral mass”. The accurate mass of a metabolite is given herein in Daltons (Da), or a mass substantially equivalent thereto. By “substantially equivalent thereto”, it is meant that a +/−5 ppm (part per million) difference in the accurate mass would indicate the same metabolite, as would be recognized by a person of skill in the art. The mass accuracy is the difference which is observed between the theoretical mass and a measured mass: delta mass accuracy (Δm)=mreal−mmeasured, which is often expressed in parts per million (ppm). Ppm is defined as 1,000,000*Δm accuracy/mmeasured (for example, theoretical mass: 1000, measured mass: 999.9 error: 100 ppm).

The accurate mass is given as the mass of the neutral metabolite. As would be recognized by a person of skill in the art, the ionization of the metabolites, which occurs during analysis of the sample, the metabolite will cause either a loss or gain of one or more hydrogen atoms and a loss or gain of an electron. This changes the accurate mass to the “ionized mass”, which differs from the accurate mass by the mass of hydrogens and electrons lost or gained during ionization. Unless otherwise specified, the accurate neutral mass will be referred to herein.

Similarly, when a metabolite is described by its molecular formula or structure, the molecular formula or structure of the neutral metabolite will be given, unless otherwise specified. Naturally, the molecular formula or structure of the ionized metabolite will differ from the neutral molecular formula or structure by the number of hydrogens lost or gained during ionization.

Data is collected during analysis and quantifying data for one or more than one metabolite is obtained. “Quantifying data” is obtained by measuring the levels or intensities of specific metabolites present in a sample. The measurement itself could be a relative measurement (e.g. comparison of intensity to another sample or distribution), or a quantitative measurement (e.g. a concentration such as X mg/ml).

The quantifying data is compared to corresponding data from one or more than one reference sample. The “reference sample”, also referred to herein as a “control sample”, is any suitable reference sample for the particular disease state. For example, and without wishing to be limiting in any manner, in the present invention the reference sample may be a sample from a control individual, i.e., a person not suffering from prostate cancer (also referred to herein as a “normal”, “control”, or “reference” individual or patient); the reference sample may also be a sample obtained from a patient with prostate cancer. As would be understood by a person of skill in the art, more than one reference sample may be used for comparison to the quantifying data. For example and without wishing to be limiting, the one or more than one reference sample may be a first reference sample obtained from a control individual. The one or more than one reference sample may also be a sample obtained from a patient at an earlier date; this would allow longitudinal monitoring of a patient's health state throughout their lifetime. Such samples could be collected over successive intervals of time. In another example, the reference sample could also be obtained from a patient with prostate cancer prior to therapy (i.e., pre-therapy) in order to monitor the efficacy of the therapy administered. A person of skill in the art would also recognize that a combination of such reference samples could be used in the methods of the present invention.

The present invention also provides novel compounds, identified using the methods of the present invention. The novel compounds may be used as metabolite markers in the diagnosis of prostate cancer or the risk of developing prostate cancer, as described above.

In one embodiment, the compounds may be selected from the metabolites listed in Table 1, or any combination thereof. An optimal panel of metabolites may be selected from the group of 492 metabolites shown in Table 1. For example, and without wishing to be limiting, the optimal panel of metabolite markers may be metabolites with accurate masses (measured in Daltons) of 519.3328, 541.3148, 545.3460, 555.3101, 541.3422, 565.3394, 521.3480, 517.3148, 567.3546, 523.3640, 531.3123, 481.3171, 495.3328, 569.3687, where a +/−5 ppm difference would indicate the same metabolite. In particular, it is presently shown that the 14 metabolites just described, when measured in serum or tissue, show a lower concentration in prostate cancer-positive subjects relative to control (disease-free) individuals.

The 14 metabolite markers described above can be categorized into one of two groups, based on their detection in an aqueous extract and their propensity to ionize either positively or negatively. The metabolites with accurate masses (measured in Daltons) of 495.3328, 517.3148, 519.3328, 521.3480, 523.3640, 541.3148, and 545.3460, where a +/−5 ppm difference would indicate the same metabolite, were detected as positive ions using methods presently described; metabolites with accurate masses (measured in Daltons) of 481.3171, 531.3123, 541.3422, 555.3101, 565.3394, 567.3546, and 569.3687, where a +/−5 ppm difference would indicate the same metabolite, were detected as negative ions using the methods presently described.

The 14 metabolites described above relate to metabolites of the lysophospholipid class, for example, lysophosphatidylcholine, lysophosphatidylethanolamines, lysophosphatidyldimethylethanolamines, lysophosphatidylserines, lysosphingosyl-phosphorylcholines, lysophosphatidylglycerols, lysophosphatidylinositols, platelet activating factors (PAFs), and combinations thereof.

The concentration of specific metabolites described above, including lysophospholipid species, is detected in order to diagnose prostate cancer or the risk of prostate cancer. Any combination of the above metabolites could be measured simultaneously, in a serial manner, or in different combinations to arrive at a diagnostic output.

Structural characterization of the above metabolites may be carried out using methods well known to those skilled in the area. The principal characteristics that may be used to characterize the metabolites may include, but are not limited to accurate mass, molecular formula, polarity, acid/base properties, NMR spectra, and MS/MS or MSn spectra. Techniques used to determine these characteristics include, but are not limited to reverse phase LC-MS using a C18 column followed by analysis by MS, MS/MS fragmentation using collision induced dissociation (CID), NMR, and extraction. The data obtained can be used as fingerprints or unique identifiers of a particular metabolite under the experimental conditions specified. Any or all of the metabolites described by the present application may be fingerprinted under various conditions to provide additional information on the metabolites, for example, the structure or nature of the molecule.

The metabolites within the optimal panel of metabolite markers described above can be further characterized by their MS/MS fragmentation patterns resulting from collision induced dissociation. In particular, metabolite with: accurate mass 495.3328 has an ionized mass of 496.3401 ([M+H]⁺, calcd. 496.3398 for C₂₄H_(5i)NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 496 ([M+H]⁺, 90%), 478 (5%), 419 (1%), 313 (1%), 283 (1%), 258 (1%), 239 (1%), 184 (90%), 166 (1%), 104 (100%), 86 (70%); see FIG. 7, Table 3.

accurate mass 517.3148 has an ionized mass of 518.3219 ([M+H]⁺, calcd. 518.3241 for C₂₆H₄₉NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 518 ([M+H]⁺, 90%), 459 (10%), 415 (1%), 359 (1%), 341 (1%), 313 (1%), 281 (1%), 221 (1%), 104 (100%), 86 (30%); see FIG. 8, Table 4.

accurate mass 519.3328 has an ionized mass of 520.3401 ([M+H]⁺, calcd. 520.3398 for C₂₆H₅₁NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 520 ([M+H]⁺, 10%), 502 (1%), 461 (5%), 281 (1%), 221 (1%), 184 (100%), 166 (5%), 124 (1%), 86 (30%); see FIG. 9, Table 5.

accurate mass 521.3480 has an ionized mass of 522.3554 ([M+H]⁺, calcd. 522.3554 for C₂₆H₅₃NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 522 ([M+H]⁺, 100%), 504 (7%), 478 (1%), 357 (1%), 258 (1%), 221 (1%), 184 (60%), 124 (5%), 104 (80%), 86 (30%); see FIG. 10, Table 6.

accurate mass 523.3640 has an ionized mass of 524.3713 ([M+H]⁺, calcd. 524.3711 for C₂₆H₅₅NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 524 ([M+H]⁺, 100%), 506 (5%), 496 (1%), 478 (1%), 331 (1%), 313 (1%), 285 (1%), 258 (1%), 184 (70%), 166 (2%), 124 (5%), 104 (70%), 86 (30%); see FIG. 11, Table 7.

accurate mass 541.3148 has an ionized mass of 542.3219 ([M+H]⁺, calcd. 542.3241 for C₂₈H₄₉NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 542 ([M+H]⁺, 80%), 483 (25%), 284 (1%), 225 (1%), 184 (1%), 104 (100%), 86 (30%); see FIG. 12, Table 8.

accurate mass 545.3460 has an ionized mass of 546.3534 ([M+H]⁺, calcd. 546.3554 for C₂₈H₃₅NO₇P⁺). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 546 ([M+H]⁺, 90%), 528 (1%), 514 (1%), 487 (30%), 104 (100%), 86 (30%); see FIG. 13, Table 9.

accurate mass 481.3171 has an ionized mass of 480.3091 ([M−H]⁻, calcd. 480.3081 for C₂₃H₄₇NO₇P⁻). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 480 ([M−H]⁻, 100%), 255 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 14, Table 12.

accurate mass 531.3123 has an ionized mass of 530.3035 ([M−H]⁻, calcd. 531.3114 for C₃₀H₄₆NO₅P). The MS/MS fragments (MS/MS m/z) (relative intensity) are: (530, 100%), 480 (100%), 255 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 15, Table 13.

accurate mass 541.3422 has an ionized mass of 540.3335 [M−H]⁻, calcd. 540.3293 for C₂₅H₅₁NO₉P⁻). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 540 ([M−H]⁻, 10%), 480 (100%), 255 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 16, Table 14.

accurate mass 555.3101 has an ionized mass of 554.3013 ([M−H]⁻, calcd. 555.3172 for C₂₅H₅₀NO₁₀P). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 554 ([M−H]⁻, 10%), 494 (100%), 269 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 17, Table 15.

accurate mass 565.3394 has an ionized mass of 564.3306 ([M−H]⁻, calcd. 564.3293 for C₂₇H₅₁NO₉P⁻). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 564 ([M−H]⁻, 100%), 504 (100%), 279 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 18, Table 16.

accurate mass 567.3546 has an ionized mass of 566.3459 ([M−H]⁻, calcd. 566.3449 for C₂₇H₅₃NO₉P⁻). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 566 ([M−H]⁻, 10%), 506 (100%), 281 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 19, Table 17.

accurate mass 569.3687 has an ionized mass of 568.3598 ([M−H]⁻, calcd. 568.3605 for C₂₇H₅₅NO₉P⁻). The MS/MS fragments (MS/MS m/z) (relative intensity) are: 568 (m/z represents the [M+H]⁺ mass), 10%), 508 (100%), 283 (100%), 242 (10%), 224 (15%), 168 (10%), 153 (10%), 79 (25%); see FIG. 20, Table 18.

Based on the structural characterization of the 14 metabolite markers selected for the diagnosis of prostate cancer, it was determined that the metabolites are molecules related to lysophospholipids. Specifically these include, but are not limited to, lysophosphatidylcholine (lysoPC), lysophosphatidylethanolamine (lysoPE), lysophosphatidyldimethylethanolamine (lysoPdmE), lysophosphatidylserine (lysoPS), lysophosphatidylinositol (lysoPI), and lysophosphatidylglycerol (lysoPG), and platelet activating factors (PAFs), wherein the glycerol backbone is attached to a fatty acid at either SN1 or SN2, for example, 16:0, 18:0, 18:1, 18:2, 18:3, 20:3, 20:4, 20:5, 22:6, ceramide, or other, and a phosphate-containing choline, ethanolamine, dimethylethanolamine, serine, glycerol, or inositol is present at SN3.

Phosphatidylcholine (PC) and phosphatidyethanaolamine (PE) represent the two major lipid components of biological membranes. PC and PE comprise a glycerol backbone containing a phosphate group attached to ethanolamine or choline at the SN3 position, and two fatty acids bound to the SN1 and SN2 positions through an acyl, ether, or vinyl-ether linkages. The fatty acids can be either saturated (more common at SN1), or unsaturated (more common at SN2). When phospholipids such as PC and PE are hydrolyzed by various phospholipases, a lysophospholipid such as lysoPC is generated along with a free fatty acid. Lysophospholipids have been implicated in numerous biological pathways and diseases, such as calcium signaling, atherosclerosis and inflammation (12).

U.S. Published Patent Application US 2004/0137541 (Mills et al.) focuses on the elevation of lysoPCs as key events in or during the progression of cancer. In particular, Mills et al. describe the elevation of lysoPCs in gynecological cancers. This is in contrast with the present invention, which shows that the panel of 14 biomarkers (i.e., metabolites with accurate masses of 519.3328, 541.3148, 545.3460, 555.3101, 541.3422, 565.3394, 521.3480, 517.3148, 567.3546, 523.3640, 531.3123, 481.3171, 495.3328, 569.3687) are decreased in the serum of patients with prostate cancer.

The present invention also provides high-throughput methods for the diagnosis of prostate cancer. The method involves fragmentation of the parent molecule; in a non-limiting example, this may be accomplished by a Q-Trap™ system. Detection of the metabolites may be performed using one of various assay platforms, including colorimetric chemical assays (UV, or other wavelength), antibody-based enzyme-linked immunosorbant assays (ELISAs), chip-based and polymerase-chain reaction for nucleic acid detection assays, bead-based nucleic-acid detection methods, dipstick chemical assays or other chemical reaction, image analysis such as magnetic resonance imaging (MRI), positron emission tomography (PET) scan, computerized tomography (CT) scan, nuclear magnetic resonance (NMR), and various mass spectrometry-based systems.

In a further embodiment of the present invention, there is provided a method for diagnosing prostate cancer or the risk of prostate cancer in a patient. The method comprising the steps of:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifiying data for one or         more than one metabolite marker;     -   c) obtaining a ratio for each of the one or more than one         metabolite marker to an internal control metabolite;     -   d) comparing each ratio of said one or more than one metabolite         marker to the internal control metabolite to corresponding data         obtained from one or more than one reference sample; and     -   e) using said comparison to diagnose prostate cancer or the risk         of prostate cancer.

The step of analyzing the sample (step b) may comprise analyzing the sample using a mass spectrometer (MS). For example, and without wishing to be limiting, such mass spectrometer could be of the FTMS, orbitrap, time of flight (TOF) or quadrupole types. Alternatively, the mass spectrometer could be equipped with an additional pre-detector mass filter. For example, and without wishing to be limiting such instruments are commonly referred to as quadrupole-FTMS (Q-FTMS), quadrupole-TOF (Q-TOF) or triple quadrupole (TQ or QQQ). In addition, the mass spectrometer could be operated in either the parent ion detection mode (MS) or in MSn mode, where n>=2. MSn refers to the situation where the parent ion is fragmented by collision induced dissociation (CID) or other fragmentation procedures to create fragment ions, and then one or more than one of said fragments are detected by the mass spectrometer. Such fragments can then be further fragmented to create further fragments. Alternatively, the sample could be introduced into the mass spectrometer using a liquid or gas chromatographic system or by direct injection.

In the method as just described above, the one or more than one reference sample may be a first baseline reference sample obtained from a control individual.

In the method as described above, the one or more than one metabolite marker may be selected from the metabolites as listed in Table 1, or the metabolites may be the 14 metabolites described above. The “internal control metabolite” refers to an endogenous metabolite naturally present in the patient, provided the metabolite is not associated with the disease and does not vary over disease states; alternatively, the “internal control metabolite” may also refer to an external standard spiked into a serum sample prior to analysis. For example, and without wishing to be limiting, the ratio may be used to determine a diagnostic score for the test subject.

Use of the ratio of the metabolite marker to the internal control metabolite offers measurements that are more stable and reproducible than measurements of absolute levels of the metabolite marker. As the internal control metabolite is present in all samples and does not vary over disease states, the sample-to-sample variability (due to handling, extraction, etc) is minimized.

In the diagnostic methods of the present invention, the measurement of metabolite markers could be taken longitudinally over time in a test subject to determine the change in metabolite concentrations and likelihood of prostate cancer, or risk for the development of prostate cancer. The test subject would provide a sample at a start point, essentially establishing a baseline value; the test subject could then provide samples over time which would be compared to the start point sample. For example, and without wishing to be limiting, an increase in the intensity of the 14 metabolites described above would indicate a reduced risk of prostate cancer, while a decrease in the intensity would indicate an increased risk for prostate cancer.

In yet another embodiment of the present invention, there is provided a method for evaluating the efficacy of a therapy for treating prostate cancer in a patient, comprising:

-   -   a) obtaining a sample from said patient;     -   b) analyzing said sample to obtain quantifying data for one or         more than one metabolite marker;     -   c) comparing said quantifying data to corresponding data         obtained from one or more than one reference sample; and     -   d) using said comparison to determine whether the therapy is         improving the health state of the patient.

Optionally, after the step of analyzing (step b), a ratio for each of the one or more than one metabolite marker to an internal control metabolite may be obtained. In this case, each ratio of said one or more than one metabolite marker to the internal control metabolite to corresponding data obtained from one or more than one reference sample is compared to evaluate the efficacy of the therapy.

The step of analyzing (step b) may comprise analyzing the sample by liquid chromatography mass spectrometry (LC-MS), or alternatively may comprise analyzing the sample by direct injection or liquid chromatography and linear ion trap tandem mass spectrometry when the method is a high-throughput method.

By the term “therapy” or “treatment”, it is meant any suitable course of therapy that may attempt to improve the health state of the patient being evaluated. When evaluating the efficacy of the therapy, the effect of the particular therapy in improving or degrading the health state of the patient will be measured. In doing so, a person of skill in the art would be capable of determining whether the therapy is effective for treating prostate cancer. Such treatment may include, but are not limited to, immunotherapy (for example, Bacillus Calmette-Guerin injection), radical prostatectomy, chemotherapy, radiation therapy, hormone therapy (including antiandrogens), or others.

In the method as described, the one or more than one reference sample may be any suitable reference sample. For example, and without wishing to be limiting in any manner, the reference sample may be a plurality of samples obtained from control individuals or one or more than one pre-therapy baseline sample obtained from the patient; or any combination thereof. A pre-therapy baseline sample from the patient is particularly useful, as the variation in metabolites will then be specific to the patient.

In the method as described above, the one or more than one metabolite marker may be selected from the metabolites as listed in Table 1, or the metabolites may be the 14 metabolites described above.

The efficacy of a therapy as described above is evaluated based on the measurement of the metabolites and comparison to the reference sample, whereby a restoration of the metabolites towards a normal specified range would be indicative of a positive treatment effect.

In an alternative method of evaluating the efficacy of a therapy for treating prostate cancer, a ratio for each of the one or more than one metabolite marker to an internal control metabolite can be obtained in step b); each ratio of the one or more than one metabolite marker to the internal control metabolite could then be compared to corresponding data obtained from one or more than one reference sample in step c).

The present invention also provides high throughput methods for diagnosis of prostate cancer. The method may involve fragmentation of the parent molecule; in a non-limiting example, this may be accomplished by a Q-Trap™ system. Detection of the metabolites may be performed using one of various assay platforms, including colorimetric chemical assays (UV, or other wavelength), antibody-based enzyme-linked immunosorbant assays (ELISAs), chip-based and polymerase-chain reaction for nucleic acid detection assays, bead-based nucleic-acid detection methods, dipstick chemical assays or other chemical reaction, image analysis such as magnetic resonance imaging (MRI), positron emission tomography (PET) scan, computerized tomography (CT) scan, nuclear magnetic resonance (NMR), and various mass spectrometry-based systems.

The HTS method may involve the measurement of intensity, peak area or summed scans of each selected daughter ion per biomarker, as well as daughter ions for one or more internal standards added to each sample. A ratio may then be generated by dividing each biomarker transition by an internal standard transition. The internal standard provides an indication of the instrument sensitivity, and allows for the normalization of biomarker transition signals across multiple samplings. The ratios generated for the disease-free or healthy population become the defining parameter for the “normal” distribution. A validation set of samples comprising normals and prostate-positives are then analyzed and compared to the normal distribution. This results in essentially two distributions, one for the normal population and one for the prostate-positive population. A cutoff ratio between the two distributions is then selected to determine the sensitivity and specificity of the biomarker assay.

In the methods of the present invention, any individual or combination of metabolites described herein could be combined with existing cancer markers to arrive at a diagnostic/prognostic output. Such existing markers may include, but are not limited to prostate specific antigen (PSA), carcinoembryonic antigen (CEA), cancer antigen (CA) 19-9, C15-3, or CA125.

The above methods may provide medical professionals with a test to better determine the appropriate treatment regimen for a subject based upon the stage at which the cancer is detected. Since the diagnostic methods are relatively non-invasive, a large number of otherwise undiagnosed cases could be identified, particularly early cases, for which specific interventions may be administered by medical professionals. The methods of the present invention may also be used to detect recurrence of cancer, possibly prior to clinical symptoms of the recurrence. Such knowledge could be subsequently used to properly direct treatment regimens that may have improved chances of preventing the recurrence.

The impact of the present invention on the diagnosis of prostate cancer would be tremendous, as literally everyone could be screened longitudinally throughout their lifetime to assess risk. Given that the performance characteristics of the test of the present invention are representative for the general population, this test alone may be superior to any other currently available screening method, as it may have the potential to detect disease progression prior to the emergence of clinical symptoms.

The present invention will be further illustrated in the following examples. An outline of the present invention including each of the examples listed below is shown in FIG. 1.

EXAMPLES

The following examples are provided to illustrate embodiments of the present invention but they are by no means intended to limit its scope.

Example 1 Discovery and Identification of Differentially Expressed Metabolites

Differentially expressed metabolites are identified in clinically diagnosed prostate cancer-positive patients and normal patients.

Clinical Samples.

For the prostate cancer screening assay described, serum samples were obtained from representative populations of healthy prostate cancer-free individuals and of professionally diagnosed prostate cancer-positive patients (SeraCare LifeSciences, Inc). The biochemical markers of prostate cancer described below were derived from the analysis of 24 serum samples from prostate cancer-positive patients and 25 serum samples from healthy controls. Samples in both groups were from a diverse population of individuals, ranging in age, ethnicity, weight, occupation, and displaying varying non-prostate cancer-related health-states. All samples were single time-point collections, and the prostate cancer samples were taken either immediately prior to, or immediately following surgical resection of a tumor. All samples were taken prior to chemo or radiation therapy.

The metabolites contained within the 49 serum samples were separated into polar and non-polar extracts by sonication and vigorous mixing (vortex mixing).

The analysis of serum extracts (24 prostate cancer, 25 normal) was made by direct injection into a FTMS and ionization by either electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) in both positive and negative modes. Sample extracts were diluted either three or six-fold in methanol:0.1% (v/v) ammonium hydroxide (50:50, v/v) for negative ionization modes, or in methanol:0.1% (v/v) formic acid (50:50, v/v) for positive ionization modes. For APCI, sample extracts were directly injected without diluting. All analyses were performed on a Bruker Daltonics APEX III Fourier transform ion cyclotron resonance mass spectrometer equipped with a 7.0 T actively shielded superconducting magnet (Bruker Daltonics, Billerica, Mass.). Samples were directly injected using ESI and APCI sources at a flow rate of 600 μL per hour. Ion transfer/detection parameters were optimized using a standard mix of serine, tetra-alanine, reserpine, Hewlett-Packard tuning mix and the adrenocorticotrophic hormone fragment 4-10. In addition, the instrument conditions were tuned to optimize ion intensity and broad-band accumulation over the mass range of 100-1000 amu according to the instrument manufacturer's recommendations. A mixture of the abovementioned standards was used to internally calibrate each sample spectrum for mass accuracy over the acquisition range of 100-1000 amu.

In total six separate analyses comprising combinations of extracts and ionization modes were obtained for each sample:

Aqueous Extract

-   -   1. Positive ESI (analysis mode 1101)     -   2. Negative ESI (analysis mode 1102)

Organic Extract

-   -   3. Positive ESI (analysis mode 1201)     -   4. Negative ESI (analysis mode 1202)     -   5. Positive APCI (analysis mode 1203)     -   6. Negative APCI (analysis mode 1204)

Mass Spectrometry Data Processing.

Using a linear least-squares regression line, mass axis values were calibrated such that each internal standard mass peak had a mass error of <1p.p.m. compared with its theoretical mass. Using XMASS software from Bruker Daltonics Inc., data file sizes of 1 megaword were acquired and zero-filled to 2 megawords. A sinm data transformation was performed prior to Fourier transform and magnitude calculations. The mass spectra from each analysis were integrated, creating a peak list that contained the accurate mass and absolute intensity of each peak. Compounds in the range of 100-2000 m/z were analyzed. In order to compare and summarize data across different ionization modes and polarities, all detected mass peaks were converted to their corresponding neutral masses assuming hydrogen adduct formation. A self-generated two-dimensional (mass vs. sample intensity) array was then created using DISCOV Ametrics™ software (Phenomenome Discoveries Inc., Saskatoon, SK, Canada). The data from multiple files were integrated and this combined file was then processed to determine all of the unique masses. The average of each unique mass was determined, representing the y axis. This value represents the average of all of the detected accurate masses that were statistically determined to be equivalent. Considering that the mass accuracy of the instrument for the calibration standards is approximately 1 ppm, it would be evident to one skilled in the art that these average masses would include all masses that fall within +/−2 ppm of this average mass, or even +/−5 ppm of this average mass. A column was created for each file that was originally selected to be analyzed, representing the x axis. The intensity for each mass found in each of the files selected was then filled into its representative x,y coordinate. Coordinates that did not contain an intensity value were left blank. Once in the array, the data were further processed, visualized and interpreted, and putative chemical identities were assigned. Each of the spectra were then peak picked to obtain the mass and intensity of all metabolites detected. These data from all of the modes were then merged to create one data file per sample. Then, the data from all 90 samples was merged and aligned to create a two-dimensional metabolite array in which each sample is represented by a column and each unique metabolite is represented by a single row. In the cell corresponding to a given metabolite sample combination, the intensity of the metabolite in that sample was displayed. When the data was represented in this format, metabolites showing differences between groups of samples (i.e., normal and cancer) were determined.

Advanced Data Interpretation.

A student's T-test was used to select for metabolites that differ between the normal and the prostate cancer-positive samples (p<0.05). 492 metabolites met this criterion (as listed in Table 1). Each of these features differs statistically between the two populations and therefore each has potential diagnostic utility. The features are described by their accurate mass and analysis mode, which together are sufficient to provide the putative molecular formulas and chemical characteristics (such as polarity and putative functional groups) of each metabolite. The ability of the 492 metabolites to discriminate between the control and prostate cancer serum is shown by the PCA plot in FIG. 2. A relatively clear distinction (as shown by the dotted line) between the controls (in grey) and prostate cancers (in black) can be drawn, which indicates that the 492 metabolites together can diagnose a prostate cancer-positive serum sample relative to control serum.

However, the incorporation and development of 492 signals into a commercially useful assay is not practical, therefore a combination of univariate analyses and chemical information was used to further select a subset of 14 metabolites from the 492 for additional characterization. The subset of 14 metabolites selected were detected in two different modes: those with accurate masses (measured in Daltons) of 495.3328, 517.3148, 519.3328, 521.3480, 523.3640, 541.3148, and 545.3460, where a +/−5 ppm difference would indicate the same metabolite, were detected as positive ions using methods described in this application and metabolites with accurate masses (measured in Daltons) of 481.3171, 531.3123, 541.3422, 555.3101, 565.3394, 567.3546, and 569.3687 were detected as negative ions using the methods described within this application. All metabolite masses represent ¹²C molecules.

The diagnostic accuracy of the 14 masses is shown through a PCA plot in FIG. 3, which illustrates a clear separation between disease and controls. In fact, separating the controls from the prostate cancers using the dotted line results in a sensitivity of 84% and specificity of 100%. A graph of the relative intensities of the 14 masses as detected on the FTICR is shown in FIG. 4 (using data scaled between 0 and 1 for each mass). Each of the markers appears to show a reduction or deficiency of approximately 50% (on average) in the prostate cancer sera versus control sera.

Based upon these results, a clear distinction can be made between the serum of prostate cancer-positive patients and healthy (prostate cancer negative) individuals. Therefore, these markers, which are capable of identifying and distinguishing prostate cancer-positive and prostate cancer-negative serum, can form the basis for a prostate cancer diagnostic test as presently described.

Example 2 Independent Method Confirmation of Discovered Metabolites

The metabolites and their associations with the clinical variables described in Example 1 were further confirmed using an independent mass spectrometry system. Representative aqueous sample extracts from each variable group (10 controls and 9 prostate cancers) were re-analyzed by LC-MS using an HP 1050 high-performance liquid chromatography, or equivalent interfaced to an ABI Q-Star, or equivalent mass spectrometer to obtain mass and intensity information for the purpose of identifying metabolites that differ in intensity between the clinical variables under investigation. Data were acquired using full-scan detection in both positive and negative ESI modes, and the resulting spectral data calibrated and aligned using Phenomenome Profiler software. We identified a retention time window (time at which molecular species are eluting off of the HPLC column), of approximately 28 to 34 minutes under the specified chromatographic conditions. FIG. 5 shows the extracted mass spectra within this retention time range for the controls (A), prostate cancers (B), and the net difference between the controls and prostate cancers (C). The boxed region shows the mass range where the subset of 14 masses previously described was redetected. As previously observed, these molecules were significantly lower in intensity in the prostate cancer sera compared to the controls. A bar graph of the average raw intensities (scaled between 0 and 1) for each of the 14 metabolites as detected using HPLC-coupled TOF-MS, is shown in FIG. 6.

Example 3 MS/MS Characterization of the 14 Metabolite Subset

Various characteristics can be used for structure elucidation of metabolites include accurate mass and molecular formula determination, polarity, acid/base properties, NMR spectra, and MS/MS or MSn spectra. These data can be used as fingerprints of a particular metabolite and are unique identifiers of a particular metabolite regardless of whether the complete structure has been determined. The data include:

1. LC Retention Time.

The extracts containing the metabolites of interest are subjected to reverse phase LC-MS using a C18 column and analysis by MS to determine their retention time under standardized conditions. When the extracts were subjected to LC/MS analysis, all 14 metabolites co-eluted within 26-34 min range.

2. MS/MS Spectra.

The 14 metabolites of interest were further characterized by performing MS/MS fragmentation using collision induced dissociation (CID). This MS/MS analysis was performed in real time (i.e. during the chromatographic elution process) or off-line on fractions collected from the chromatographic separation process.

Aqueous fractions from 9 prostate cancer and 10 normal sample extracts were evaporated to dryness under nitrogen gas and reconstituted in 100 μL of water:methanol:formic acid (97.9:2:0.1). 5 μL of the reconstituted sample was used for HPLC (Agilent 1100 system with MetaSil AQ 3 um, C18, 100×2 0 mm column, Varian Inc.) for full scan and MS/MS. The mobile phase consisted of water:methanol:formic acid (97.9:2:0.1) as solvent A, and 0.1% formic acid in methanol as solvent B. At a flow rate of 0.2 ml/min, the solvent gradient was as follows: Solvent A was held at 100% for the first minute, then changed to 20% A and 80% B using a linear gradient over 10 min, and then held at 20% A, 80% B for 9 min; then the solvent mixture was changed to 100% B during the next 10 min using a linear gradient, and was held at 100% B for 15 minutes. Finally, the solvent mixture was held at 100% A to equilibrate the column for duration of 20 min (total elapsed time 65 min). Eluate from the HPLC was analyzed using an ABI QSTAR® XL mass spectrometer fitted with an ESI (TurboIonSpray™) source in positive and negative mode.

For time-of-flight full scan mode, the “TOF-MS” scan type was used with an accumulation time of 1.0 sec, a mass scan range of 50 to 1500 Da, and duration time of 60 min. The source parameters at positive ESI mode were as follows: Ion source gas 1 (GS1) 55; Ion source gas 2 (GS2) 90; Curtain gas (CUR) 40; Nebulizer Current (NC) 3.0; Temperature 400° C.; Declustering Potential (DP) 60; Focusing Potential (FP) 265; Declustering Potential 2 (DP2) 15. The source parameters at negative ESI mode were as follows: Ion source gas 1 (GS1) 55; Ion source gas 2 (GS2) 70; Curtain gas (CUR) 40; Nebulizer Current (NC) 0; Temperature 400° C.; Declustering Potential (DP)-55; Focusing Potential (FP)-265; Declustering Potential 2 (DP2)-15.

In MS/MS mode, the “Product Ion” scan type was used with an accumulation time of 1.0 sec, a scan range of 50 to 650 Da, and a duration time of 60 min. All source parameters are the same as above, with collision energy (CE) settings of 20V, 35V, 50V at positive mode and −20V, −35V, −50V at negative mode. The collision gas (CAD, nitrogen) was set at 5.

The structure of a given molecule dictates a specific fragmentation pattern under defined conditions and is unique for that molecule (equivalent to a person's fingerprint)—even slight changes to the molecule's structure can result in a different fragmentation pattern. In addition to providing a fingerprint of the molecule's identity, the fragments generated by CID were used to gain insights regarding the structure of the metabolites.

Upon constructing possible molecular formulae for the positive mode biomarker panel (i.e., metabolites with accurate masses of 495.3328, 517.3148, 519.3328, 521.3480, 523.3640, 541.3148, and 545.3460), all seven biomarkers were found to possess similar formulae of RNO₇P, where R is the variable fatty acid type, indicating that they could be phospholipid choline-related compounds. A summary of the proposed structures based upon MS/MS interpretations is shown in Table 2. The fragmentation spectra for the 7 metabolites detected in the positive ionization mode are shown in FIGS. 7 to 13 (collision energies of 20 (A), 35 (B) and 50 (C) volts), and the masses of the fragments and molecular formula assignments listed in Tables 3 through 9. Each table lists the daughter ions resulting from the CID, as well as the proposed structures of the fragment ions and the fragment losses.

The MS/MS data obtained in the positive mode ESI indicates that each of the seven metabolites abstracted a proton, resulting in the corresponding molecular ion ([M+H]⁺) in their MS/MS spectra. This suggests the protonation of the phosphate group leaving the positively charged quaternary ammonium ion as the parent ion. Evidence for losing the quaternary amine group, (CH₃)₃NH⁺, [M+H-60]⁺) was observed for all of the metabolites confirming the presence of the choline head group in these metabolites. Fragment ions due to phosphocholine (C₅H₁₅NO₄P⁺, m/z 184) and ethanol-quaternary amine (C₅H₁₄NO⁺, m/z 104) were other indications suggesting phosphocholine-type structures. Loss of H₂O from the molecular ions was also observed confirming the presence of free hydroxy groups at sn-2 positions inherent in lysolipid-type structures.

Fragment ions, though weak, were observed for either a sn-1 fatty acid side chain or loss thereof. For example, for metabolite 495.3328, where palmitic acid was thought to be the sn-1 fatty acid, the fragment ion representing m/z 458 was assigned as plausibly due to the loss of C₁₆H₃₂O unit. Another fragment ion at m/z 239 (C₁₆H₃₁O⁺) though low in intensity was also present signifying the sn-1 fatty acid itself. Based on these deductions, the structure was proposed as 2-hydroxy-1-palmitoyl-sn-glycero-3-phosphocholine. The structure of 495.3328 was confirmed to be 2-hydroxy-1-palmitoyl-sn-glycero-3-phosphocholine (commercial standard) by comparison of their LC/MS and MS/MS spectral data (fragment ion comparisons shown in Table 10).

The MS/MS spectral data of the remaining 6 metabolites were very similar to that of 495.3328, the only differences being differences in the sn-1 fatty acid side chains. For metabolites 519.3328 (520 M−H), 521.3481 (522 M−H), and 523.3640 (524 M−H), loss of H₂O from their parent ions resulted in fragment ions m/z 518, 520 and 522 respectively suggesting that their fatty acid side chains varied with an increasing degree of unsaturation. For 520, the sn-1 side chain was deduced as linoleic acid due to the fragment ion at m/z 281. In 522 and 524, a common fragment ion at m/z 258, was thought to be due to the loss of oleyl (C₁₈H₃₃O) and stearyl (C₁₈H₃₅O) substituents from their parent ions thus confirming oleic and stearic acid side chains respectively. For metabolite 541.3148 (542 M−H), the fragment ion at m/z 225 was deduced as loss of eicosapentenoic side chain. Using the above discussed MS/MS data, the structures of these 7 prostate cancer biomarkers proposed as shown in Table 2.

The fragmentation spectra of the seven metabolites detected in the negative ionization mode (i.e., metabolites with accurate masses of 481.3171, 531.3123, 541.3422, 555.3101, 565.3394, 567.3546, and 569.3687), are shown in FIGS. 14 to 20 (collision energies of 20, 35 and 50 volts). The molecular formulae suggested that four (541.3422, 565.3394, 567.3546, 569.3687) out of the seven biomarkers were found to possess similar formulae of RNO₉P, where R is the variable fatty acid type, indicating that they could be phospholipid ethanolamine related compounds. Table 11 summarizes the molecular formulae and putative structures of the molecules based upon the MS/MS data. Tables 12 to 18 list the fragment ion masses, putative formulas of the fragments and fragment losses as well as putative structures for each fragment.

In the negative mode with electro spray ionization, (ESI), each of the seven molecules loose a proton resulting in the corresponding molecular ion ([M−H⁺]⁻) in their MS/MS spectra. This suggests the de-protonation of the phosphate group, leaving the negatively charged phosphate ion as the parent ion. Fragment ions were observed for sn-1 fatty acid side chain for the markers 481.3168 and 541.3422 (palmityl, C₁₆H₃₁O₂, m/z 255), 565.3394 (linoleyl, C₁₈H₃₁O₂, m/z 279), 567.3546 (oleyl, C₁₈H₃₃O₂, m/z 281), and 569.3687 (stearyl, C₁₈H₃₅O₂, m/z 283) as prominent signals in their MS/MS spectra. Upon comparing the MS/MS spectra of 569.3687 to its corresponding lysophospholipid ethanolamine counterpart, 2-hydroxy-1-stearyl-sn-glycero-3-phosphoethanolamine (C₂₃H₄₈NO₇P, exact mass: 481.317) (commercial standard), a number of similarities were observed (Table 19). The initial fragment loss from the parent ion [M+H]⁻ of 569.3687 was corresponding to a mass loss of 60 Dalton unit which is associated with the formula C₂H₄O₂. This fragment loss was consistent to all the markers of the above panel with exception to 481.3171 which has a formula of C₂₃H₄₈NO₇P similar to the general formulation of the sn2-hydroxyphosphoethanolamine types. In comparing the fragment m/z 508 of 569.3687 to the parent ion of its lysophosphoetanolamine commercial standard (m/z 480), a difference of only 28 Dalton units was observed, which lead to the derivation of N,N-dimethyl phosphoethanolamine type of structures for the biomarker panel. The fragment losses after the loss of sn2 fatty acid, m/z 242, 168, 153 and 79 are constantly observed for all seven biomarkers further confirming a plausible dimethyl ethanolamine type of backbone on the molecule.

While the reported MS/MS data is consistent with molecules of lysophospholipid species, the present invention also includes structures where functional groups or reported fragments are connected in ways that are not presently indicated.

Example 4 High Throughput Commercial Method Development

A high throughput screening (HTS) method was developed for diagnosing prostate cancer. The method described below is compatible with current laboratory instrumentation and triple-quadrupole mass spectrometers that are in place in many laboratories globally (13, 14).

High throughput screening (HTS) was performed with a linear ion trap mass spectrometer (Q-trap 4000, Applied Biosystem) coupled with Agilent 1100 LC system. Serum samples were extracted as described in Example 1. The aqueous fraction was mixed 1:3 with acetonitrile to precipitate proteins prior to use for the analysis of each sample. 15 μL of internal standard (reserpine in methanol: 100 μg/mL for negative ESI; 1 μg/mL for positive ESI) and 108 μL of 3:1 (acetonitrile):(1% formic acid in ddH2O) was added to each 12 μL sample aliquot for a total volume of 135 μL. The autosampler injected 100 μL of the sample by flow-injection analysis (FIA) into an ABI 4000QTRAP. The carrier solvent was 60:40 (methanol):(1% formic acid in ddH2O), with a flow rate of 450 μL/min into the APCI source.

The MS/MS HTS methods (negative and positive ESI) were developed on a quadrupole linear ion trap ABI 4000QTRAP mass spectrometer equipped with a TurboV™ source with an Ionspray probe. The source gas parameters were as follows: Negative ESI: (CUR: 10.0, CAD: 6, IS: −4500, TEM: 500, GS1: 50, GS2: 60, interface heater on. “Compound” settings were as follows: entrance potential (EP): −10, and collision cell exit potential (CXP): −10.0); Positive ESI: (CUR: 10.0, CAD: 6, IS: 5500, TEM: 500, GS1: 30, GS2: 60, interface heater on. “Compound” settings were as follows: entrance potential (EP): 10, and collision cell exit potential (CXP): 15.0).

The methods were based on the multiple reaction monitoring (MRM) of 2 MRM transitions for each biomarker, and 2 MRM transitions for the internal standard (reserpine, though other compounds may be used) for a total of 16 MRM's for each method. Each of the transitions was monitored for 100 msec or 70 msec for positive and negative ESI modes, respectively. The total acquisition time per sample was approximately 1 min. Briefly, each method measured the intensities of each of 14 biomarker MRM transitions (from 7 parents) and 2 internal standard (IS) MRM transitions (from 1 parent) as shown in Table 20. A patient score was then generated by determining the lowest mean-normalized log(2) transformed ratio of the seven measured biomarker:IS transitions per patient. This value was then compared to a distribution of scores generated from normal individuals, and a prostate cancer risk factor was assigned accordingly. It was confirmed that the ABI 4000QTRAP was capable of accurately measuring the MRM transition peak areas using the method described above by plotting the peak area ratios of the biomarker transitions versus the internal standard transitions for each of the seven biomarkers for each method. In addition, the HTS method also incorporates a series of dilutions of extracted human reference serum material, which allowed for the determination and assurance of instrument linearity. If the calibration curve has a R² value <0.98, then the sample run is considered a failure and the sample needs to be rerun.

As described above, the prostate cancer HTS triple-quad method comprises two independent data acquisition components due to the fact that half the molecules are detected in negative mode, and the other half in positive mode.

For the seven lysophosphaditylcholine molecules detected in the positive mode (i.e., metabolites with accurate masses of 495.3328, 517.3148, 519.3328, 521.3480, 523.3640, 541.3148, and 545.3460), the transitions used for measurement are shown in FIG. 21A, and comprise two daughter ion transitions per molecule for each of the biomarkers (a and b, with the exception of 546.3, in which a single transition was used), and two internal standard transitions per sample (1 and 2). Dividing each biomarker transition by each internal standard transition therefore resulted in 26 ratios per biomarker. A normal reference serum sample is also analyzed at varying dilutions to assess instrument linearity, for which R-squared coefficients can be calculated. The average R-squared values for data obtained below for each transition ratio is shown in FIG. 21A. A sample plot of the average intensities of the dilutions for 496.3/184.2a1 is shown in FIG. 21B. The ratio data was then normalized to the mean of the control population and log(2) transformed. The lowest ratio value of per patient was then selected as the final output score. The distributions of these patient scores were then visualized to determine the optimum diagnostic cut-off point.

The same 24 prostate cancer serum samples used for the discovery phase were re-analyzed using this method, along with an expanded independent set of 147 male control samples. The average ratio (not log transformed) for each of the 26 transitions in the control and prostate cancer cohorts is shown in FIG. 21C. As expected, the intensity of each ratio is lower in the prostate cancer cohort compared to the controls.

The final patient scores (lowest detected log ratio per patient) for these subjects are shown in the scatter plot in FIG. 22A. The results clearly show that the patient scores of the 24 prostate cancer patients (black triangles) were significantly lower than most of the disease-free male subjects (light grey squares). Plotting the distributions of the subjects based upon the patient score, as shown in FIG. 22B, mirrored the previous findings and showed a shift in the distribution of the prostate patients (black bars) to the left, indicating an overall lower patient score in the majority of prostate cancer patients relative to the controls. Setting a cut-off patient score of −1.25, indicated by the dotted line in FIG. 22A, resulted in approximately 75% sensitivity (that is, 75% of the cancer patients have scores of less than −1.25), and 91% specificity (that is, 91% of the control male population has a score greater than −1.25). The p-value generated from a t-test using the patient scores was 1.09E-14 between the controls and prostate cancer samples.

For the seven lysolipid species detected in the negative mode (481.3171, 531.3123, 541.3422, 555.3101, 565.3394, 567.3546, and 569.3687), the daughter ion transitions for the HTS method are shown in FIG. 23A. The method is similar to the positive mode, with four ratios (from two internal standard measurements) generated per parent ion, resulting in 28 total ratios per patient sample. The average r-squared values resulting from the analysis of multiple diluted serum samples for each of the ratios is also shown in FIG. 23A. A plot of the standard curve for the first transition ratio (480.3/255.4a1) is shown in FIG. 23 B as an example. As expected, the ratios for each of the transitions was lower in the prostate cancer cohort relative to the controls, as shown in the bar graph in FIG. 23C.

The final patient scores (lowest detected log ratio per patient) for the seven metabolites detected in the negative mode are shown in the scatter plot in FIG. 24A. The results clearly show that the patient scores of the 24 prostate cancer patients (black triangles) were significantly lower than most of the disease-free male subjects (light grey squares). Plotting the distributions of the subjects based upon the patient score, as shown in FIG. 24B, mirrored the previous findings and showed a shift in the distribution of the prostate patients (black bars) to the left, indicating an overall lower patient score in the majority of prostate cancer patients relative to the controls. Setting a cut-off patient score of −1.00, indicated by the dotted line in FIG. 24A, results in approximately 79% sensitivity (that is, 79% of the cancer patients have scores of less than −1.00), and 81% specificity (that is, 81% of the control male population has a score greater than −1.25). The p-value generated from a t-test using the patient scores was 4.11E-14 between the controls and prostate cancer samples.

As would be known to a person of skill in the art, the cut-off value could be move either up or down to favor either sensitivity or specificity, respectively. This performance is superior to that achievable with PSA testing. Since this method is accurate and can be run rapidly on a serum sample, screening the male population would be expected to identify otherwise undetected cases, and would therefore have a major impact on prostate cancer mortality.

As would also be known to a person of skill in the art, various subsets of the measured transitions and ratios thereof could be used to optimize the diagnostic accuracy. Likewise, performing serial analysis of each of the positive and negative modes and then stacking or combining the results may also improve the sensitivity and specificity. For example, patients incorrectly diagnosed using only one method (positive mode) may be correctly classified with the negative mode, or vise-versa. Alternatively, data from both positive and negative modes could be acquired first, followed by the generation of a single patient score based upon the total cumulative dataset.

All citations are hereby incorporated by reference.

The present invention has been described with regard to one or more embodiments. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims.

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TABLE 1 List of metabolites discriminating prostate cancer-positive from normal serum (p < 0.05). Detected Analysis Avg. Normal StDev. Avg. Prostate StDev. Normal/Prostate Mass Mode P_Value (log2) Normal (log2) Prostate (log2 ratio) 174.1408 1203 0.0079 1.85 0.25 1.62 0.32 1.14 188.1566 1203 0.0227 1.46 0.36 1.12 0.63 1.31 194.0804 1203 0.0001 0.72 0.8 0 0 0.72 202.0454 1101 0.0279 2.58 1.09 3.15 0.59 0.82 205.8867 1101 0.048 2.81 0.28 2.96 0.21 0.95 216.0401 1102 0.0216 3.02 0.84 3.5 0.51 0.86 218.0372 1102 0.0137 1.35 0.78 1.85 0.58 0.73 226.0687 1102 0.0163 1.94 0.86 2.49 0.67 0.78 228.1476 1101 0.0001 0.07 0.36 1.25 1.28 0.06 232.9133 1202 0.0049 2.46 0.22 2.04 0.68 1.21 242.2251 1204 0.0024 2.02 0.32 1.68 0.42 1.2 243.0719 1101 0.0116 4.53 0.79 5.04 0.54 0.9 244.056 1101 0.0043 1.54 1.14 2.41 0.87 0.64 247.9578 1102 0.0003 0 0 1.58 2 0 252.2096 1204 0.0063 1.84 0.33 1.44 0.61 1.28 258.2482 1204 0.0421 1.97 0.33 1.77 0.33 1.11 268.2412 1204 0.0209 2.42 0.42 2.15 0.36 1.12 272.2357 1204 0.0307 2.75 0.52 2.45 0.44 1.13 273.874 1101 0.0349 2.76 0.29 2.93 0.23 0.94 276.2096 1204 0.0001 2.77 0.46 2.24 0.42 1.24 278.2256 1204 0.0013 4.95 0.42 4.54 0.42 1.09 279.2287 1204 0.0047 2.83 0.47 2.44 0.45 1.16 280.2414 1204 0.0401 8.14 0.45 7.89 0.36 1.03 281.2448 1204 0.0352 5.77 0.45 5.52 0.36 1.05 283.2602 1204 0.0475 6.56 0.42 6.33 0.38 1.04 283.9028 1101 0.0061 3.14 0.33 3.36 0.2 0.93 292.204 1204 0.0096 1.9 0.54 1.48 0.57 1.29 296.2358 1204 0.0229 4.48 0.55 4.16 0.38 1.08 298.2519 1204 0.004 4.74 0.5 4.35 0.38 1.09 299.2558 1204 0.0034 2.51 0.49 2.13 0.37 1.18 300.2098 1204 0.0026 1.83 0.33 1.37 0.64 1.34 300.2676 1204 0.0001 1.26 0.63 0.49 0.63 2.59 302.2256 1204 8.97E−06 3.69 0.4 3.05 0.5 1.21 304.2394 1202 0.0088 4.39 0.47 4.03 0.45 1.09 304.241 1204 1.34E−05 5.07 0.31 4.64 0.32 1.09 305.243 1202 0.0123 2.4 0.68 1.8 0.91 1.33 305.2439 1204 0.0001 2.77 0.32 2.34 0.36 1.19 306.257 1204 0.0003 3.14 0.39 2.65 0.5 1.19 308.2715 1204 0.0171 1.96 0.58 1.54 0.62 1.28 310.2154 1204 0.0128 2.29 0.47 1.99 0.32 1.15 310.2884 1204 0.0322 2.39 0.52 2.03 0.62 1.18 312.2313 1204 0.0018 2.69 0.33 2.41 0.26 1.12 312.304 1204 0.0013 1.22 0.82 0.51 0.62 2.41 314.2464 1204 0.0049 1.88 0.37 1.45 0.63 1.3 317.9626 1101 0.0053 0.86 1.23 1.81 1.02 0.48 320.2358 1204 4.37E−05 1.86 0.56 0.99 0.77 1.87 326.2262 1204 0.0052 1.79 1.03 0.96 0.95 1.87 326.2476 1204 0.0425 0.79 0.68 1.18 0.59 0.68 327.0326 1204 0.002 2.61 0.31 2.32 0.32 1.13 328.2628 1204 0.0356 1.75 0.25 1.93 0.31 0.91 329.2426 1202 0.0399 1.25 1 0.67 0.91 1.86 329.2445 1204 0.0147 0.91 0.83 0.39 0.59 2.33 330.2568 1204 0.0428 2.25 0.4 1.93 0.66 1.17 331.8326 1101 0.0273 2.7 0.32 2.89 0.26 0.93 339.9964 1101 0.0003 1.94 0.95 2.77 0.43 0.7 340.2977 1203 0.0156 2.4 0.41 2.12 0.36 1.13 341.8614 1101 0.017 3.34 0.39 3.58 0.27 0.93 342.2198 1204 0.0159 0.71 0.82 0.22 0.52 3.27 351.8906 1101 0.0391 3.38 0.41 3.59 0.25 0.94 354.1668 1202 0.0008 0 0 1.08 1.51 0 368.3437 1203 0.0146 10.86 0.29 10.67 0.24 1.02 369.3474 1203 0.0232 9.26 0.25 9.1 0.22 1.02 371.3538 1203 0.0087 3.05 0.27 2.84 0.26 1.07 382.2903 1204 0.0045 0.04 0.18 0.61 0.94 0.06 392.294 1204 0.0001 1.81 0.96 0.63 1 2.88 411.3186 1202 0.0044 2.99 0.29 2.74 0.3 1.09 430.3083 1204 0.0003 2.09 0.28 1.82 0.2 1.15 430.3818 1204 0.0064 4.04 0.69 3.5 0.63 1.15 431.3861 1204 0.0169 2.53 0.65 2.11 0.52 1.2 432.3686 1204 0.0107 1.6 0.9 0.87 1.01 1.84 452.2536 1204 0.0023 1.71 0.34 1.21 0.69 1.41 472.3925 1203 0.0052 3.93 0.51 4.32 0.41 0.91 473.3957 1203 0.0122 2.46 0.52 2.83 0.47 0.87 481.3171 1102 3.99E−09 1.79 0.36 0.86 0.53 2.08 481.3172 1202 0.006 4.19 0.25 3.98 0.27 1.05 482.3216 1202 0.0265 2.28 0.28 2.09 0.3 1.09 484.3792 1204 0.0432 1.8 0.7 1.32 0.89 1.36 492.4184 1203 0.0025 0.69 0.94 0.05 0.26 12.93 494.4344 1203 0.01 1.92 1.56 0.9 1.04 2.13 495.3328 1101 4.45E−08 4.22 0.38 3.23 0.65 1.3 495.4376 1203 0.023 0.81 1.11 0.22 0.51 3.63 496.336 1101 2.57E−08 2.68 0.34 1.74 0.6 1.53 501.2848 1201 0.0053 1.47 0.97 0.75 0.75 1.97 505.3227 1202 0.0005 4.17 0.3 3.85 0.3 1.08 506.3213 1202 0.0007 2.66 0.29 2.35 0.32 1.13 507.3317 1202 0.0258 3.02 0.26 2.84 0.28 1.06 509.3493 1202 0.0021 2.69 0.26 2.39 0.38 1.13 517.3148 1101 2.98E−08 4.38 0.36 3.3 0.72 1.33 518.3182 1101 5.20E−08 2.42 0.32 1.33 0.78 1.82 518.4345 1203 0.0043 1.33 1.08 0.52 0.79 2.57 519.332 1201 0.0008 2.68 0.73 2.04 0.5 1.31 519.3328 1101 2.80E−09 2.6 0.57 1.12 0.82 2.31 520.4502 1203 0.0049 3.69 0.97 2.88 0.96 1.28 521.348 1101 3.30E−09 2.35 0.38 1.34 0.57 1.75 521.4526 1203 0.0189 1.97 1.04 1.32 0.82 1.49 522.464 1203 0.0092 4.68 0.96 3.93 0.98 1.19 523.364 1101 2.06E−08 2.54 0.44 1.52 0.62 1.68 523.4678 1203 0.0083 3.27 0.93 2.55 0.91 1.28 524.4725 1203 0.0053 1.08 0.92 0.39 0.72 2.77 529.3167 1202 0.011 3.32 0.32 3.06 0.38 1.09 531.3123 1102 1.22E−09 2.39 0.3 1.49 0.51 1.61 534.4645 1204 0.039 1.34 0.8 0.85 0.83 1.58 538.501 1204 0.0479 0.93 0.86 0.48 0.71 1.97 541.3148 1101 4.07E−09 2.56 0.59 1.07 0.84 2.39 541.3422 1102 5.17E−10 4.45 0.36 3.47 0.51 1.28 541.3433 1202 0.0241 6.11 0.34 5.89 0.31 1.04 542.3453 1102 1.47E−10 2.65 0.35 1.8 0.38 1.47 542.3461 1202 0.0215 4.21 0.27 4.03 0.26 1.04 545.346 1101 3.41E−08 2.48 0.48 1.2 0.84 2.07 548.4817 1203 0.0358 6.91 0.53 6.58 0.51 1.05 549.4848 1203 0.0347 5.47 0.54 5.14 0.53 1.06 552.3825 1201 0.0061 0 0 0.43 0.75 0 552.4048 1204 0.0167 0.75 0.71 0.3 0.55 2.53 555.3101 1102 9.86E−09 1.94 0.48 0.84 0.62 2.32 565.3393 1202 0.0128 7.07 0.37 6.83 0.28 1.04 565.3394 1102 5.30E−09 4.17 0.49 3.13 0.54 1.33 566.3433 1102 7.66E−09 2.44 0.49 1.5 0.44 1.62 566.3434 1202 0.0017 5.4 0.31 5.11 0.3 1.06 567.3546 1202 0.0468 6.01 0.3 5.84 0.28 1.03 567.3548 1102 5.18E−10 3.41 0.41 2.48 0.43 1.38 568.3573 1102 1.36E−06 1.53 0.48 0.68 0.58 2.23 568.3574 1202 0.0494 4.01 0.3 3.84 0.29 1.04 569.3687 1102 6.16E−08 3.13 0.41 2.14 0.64 1.46 569.3691 1202 0.0043 5.16 0.23 4.91 0.35 1.05 570.3726 1202 0.0047 3.28 0.23 3.04 0.33 1.08 570.4653 1203 0.0021 2.21 0.39 1.71 0.65 1.29 570.4915 1204 0.0089 0.67 0.8 0.15 0.5 4.56 579.5322 1203 0.0008 4.45 0.6 3.84 0.59 1.16 580.5345 1203 0.0006 2.21 0.71 1.4 0.83 1.58 582.2469 1201 0.0261 2.44 0.97 3.02 0.8 0.81 583.2504 1201 0.042 1.11 0.83 1.58 0.75 0.7 587.3228 1202 0.0276 2.22 0.91 1.61 0.94 1.37 589.3401 1102 3.62E−07 2.73 0.42 1.86 0.6 1.47 589.3404 1202 0.0246 6.25 0.37 5.98 0.42 1.04 590.343 1202 0.0253 4.37 0.37 4.12 0.38 1.06 590.4597 1204 0.0219 2.54 0.57 2.13 0.65 1.2 596.4794 1203 0.0012 3.36 0.42 2.88 0.55 1.17 599.4932 1204 0.0151 1.76 0.91 1.07 0.99 1.64 601.5077 1204 0.0428 1.65 0.83 1.14 0.92 1.46 604.5441 1203 0.0002 6.45 0.49 5.89 0.49 1.1 605.5469 1203 0.0002 4.94 0.51 4.37 0.5 1.13 609.3242 1102 9.76E−08 2.04 0.35 1.18 0.58 1.72 612.5004 1204 0.0149 1.85 0.69 1.27 0.9 1.46 615.4797 1204 0.0001 3.22 0.37 2.77 0.38 1.16 622.4973 1203 0.0126 3.29 0.59 2.89 0.51 1.14 623.4918 1204 0.0366 1.79 0.94 1.21 0.93 1.48 623.5003 1203 0.006 2.19 0.6 1.59 0.83 1.37 624.5134 1203 0.0003 4.04 0.39 3.6 0.4 1.12 625.5078 1204 0.0259 3.76 0.64 3.36 0.54 1.12 625.5163 1203 0.0005 2.86 0.4 2.42 0.43 1.18 626.5109 1204 0.014 2.63 0.59 2.17 0.67 1.21 626.5285 1203 1.19E−05 3.78 0.36 3.28 0.37 1.15 627.5204 1204 0.015 4.62 0.59 4.21 0.55 1.1 627.5306 1203 0.0006 2.52 0.41 2.06 0.47 1.23 628.5236 1204 0.0103 3.32 0.61 2.86 0.6 1.16 628.5426 1203 0.0017 3.22 0.45 2.76 0.5 1.16 629.5453 1203 0.0275 1.95 0.66 1.46 0.83 1.33 630.5582 1203 0.0078 2.78 0.68 2.32 0.46 1.2 632.5752 1203 1.91E−06 1.46 0.85 0.3 0.61 4.83 635.5246 1204 0.0253 1.7 1 1.07 0.89 1.58 641.4915 1204 0.0036 2.19 1.03 1.19 1.23 1.83 646.5709 1203 0.0008 3.54 0.6 2.92 0.59 1.21 647.574 1203 0.0008 2.72 0.58 2.06 0.71 1.32 647.6063 1204 0.0044 2.09 0.62 1.39 0.97 1.5 648.5865 1203 0.0007 5.73 0.44 5.2 0.56 1.1 649.5056 1204 0.0255 2.61 0.91 2.02 0.91 1.3 649.5898 1203 0.0015 4.69 0.48 4.17 0.59 1.12 655.5509 1204 0.0006 2.79 0.57 1.87 1.1 1.49 660.5005 1204 0.0059 1.38 0.97 0.62 0.86 2.22 660.6082 1203 0.0116 0.41 0.77 0 0 0.41 663.4864 1204 0.0311 1.49 1.27 0.76 1.03 1.97 670.5688 1204 9.11E−06 3.86 0.42 3.2 0.51 1.21 670.5711 1203 0.0142 1.69 0.89 1.03 0.92 1.64 671.5723 1204 0.0003 2.92 0.4 2.17 0.85 1.34 672.5865 1203 0.0034 4.47 0.61 3.91 0.65 1.14 673.5893 1203 0.003 3.66 0.57 3.13 0.61 1.17 673.6185 1204 0.0174 3.07 0.49 2.63 0.74 1.17 673.6224 1203 0.0032 2.74 0.45 2.37 0.4 1.16 675.6359 1203 0.001 3.37 0.37 3 0.37 1.12 675.6375 1204 0.0047 3.89 0.48 3.33 0.82 1.17 676.6393 1203 0.0009 2.24 0.36 1.78 0.54 1.26 680.5625 1204 0.0293 3.86 0.65 3.48 0.52 1.11 684.5487 1204 0.0001 3.11 0.37 2.63 0.44 1.18 685.5543 1204 0.0001 2.7 0.37 2.1 0.61 1.29 686.5126 1204 0.0469 2.49 0.86 1.92 1.09 1.3 688.5294 1204 0.0081 2.9 0.43 2.46 0.68 1.18 690.4849 1204 0.0399 2.37 0.6 1.98 0.69 1.2 690.547 1204 0.0008 2.36 0.39 1.73 0.77 1.36 692.5571 1204 0.017 3.07 0.63 2.65 0.54 1.16 693.611 1204 0.0396 3.79 0.5 3.39 0.8 1.12 695.647 1204 0.0043 2.54 1.08 1.36 1.63 1.87 696.5856 1203 0.0318 1.14 0.98 0.59 0.73 1.93 696.651 1204 0.0448 1.53 1.17 0.81 1.28 1.89 699.5205 1204 0.0002 2.61 0.75 1.63 0.93 1.6 702.5675 1101 6.42E−08 2.87 0.29 2.12 0.5 1.35 705.6083 1204 0.0303 2.82 0.49 2.44 0.69 1.16 707.6256 1204 0.0361 4.27 0.43 3.83 0.93 1.12 708.6308 1204 0.0242 3.26 0.44 2.86 0.74 1.14 710.4923 1204 0.0087 2.32 0.37 1.91 0.65 1.22 716.4982 1204 0.0004 2.38 0.33 1.59 0.98 1.5 721.6388 1204 0.0402 5.27 0.49 4.76 1.1 1.11 722.6423 1204 0.0473 4.18 0.51 3.75 0.89 1.11 723.5194 1204 7.34E−07 4.49 0.76 3.32 0.67 1.35 723.5198 1202 4.42E−07 3.17 0.64 1.96 0.81 1.62 724.5247 1204 9.89E−07 3.45 0.69 2.32 0.72 1.49 724.5496 1101 1.87E−07 2.45 0.29 1.77 0.47 1.38 725.5375 1204 0.0002 3.23 0.84 2.23 0.87 1.45 726.5456 1204 7.10E−06 2.81 0.37 1.89 0.82 1.48 727.5565 1204 1.52E−05 3.68 0.5 2.86 0.67 1.29 728.562 1204 6.41E−07 3.01 0.36 2.23 0.58 1.35 729.5724 1204 2.18E−05 2.39 0.38 1.56 0.79 1.53 731.4913 1204 0.0013 5.85 0.37 5.45 0.44 1.07 732.4938 1204 0.0013 4.6 0.36 4.21 0.44 1.09 733.6425 1204 0.0199 3.17 0.43 2.75 0.77 1.16 735.6555 1204 0.0055 4.08 0.42 3.52 0.86 1.16 736.2234 1204 0.0037 0.05 0.26 0.77 1.15 0.07 736.6584 1204 0.0078 2.95 0.45 2.47 0.71 1.19 737.5354 1204 0.0059 1.3 1.05 0.54 0.75 2.39 738.5449 1102 1.43E−07 2.76 0.35 2.14 0.35 1.29 741.5307 1204 0.0066 2.96 0.52 2.52 0.56 1.17 742.5354 1204 0.0448 2.04 0.84 1.51 0.94 1.35 743.5469 1202 0.0499 3.47 0.45 3.23 0.38 1.07 744.4942 1204 0.0208 4.35 0.37 4.09 0.39 1.06 745.4972 1204 0.0029 3.53 0.29 3.23 0.39 1.1 746.556 1102 2.28E−05 2.02 0.3 1.37 0.62 1.47 747.5201 1202 0.0001 2.64 0.55 1.95 0.6 1.36 747.5234 1204 0.0007 3.91 0.52 3.36 0.52 1.16 748.5279 1204 0.0025 2.81 0.53 2.25 0.7 1.25 748.5722 1102 2.22E−07 4.56 0.34 3.91 0.41 1.17 749.5346 1203 0.0221 0.97 1.02 0.38 0.68 2.56 749.5354 1201 0.0001 2.15 0.62 1.31 0.73 1.64 749.5364 1202 9.54E−08 3.96 0.45 2.94 0.67 1.35 749.5402 1204 3.67E−06 5.01 0.64 4.11 0.55 1.22 749.5763 1102 8.79E−07 3.39 0.35 2.76 0.42 1.23 750.5403 1202 3.39E−07 2.93 0.44 1.99 0.65 1.47 750.5434 1204 6.74E−07 3.86 0.58 2.94 0.54 1.31 751.551 1203 0.0218 1.39 1 0.78 0.77 1.78 751.5529 1202 3.60E−06 4.09 0.52 3.18 0.69 1.29 751.5548 1204 2.96E−05 5.25 0.72 4.35 0.64 1.21 752.5565 1202 3.61E−06 3.01 0.51 2.17 0.6 1.39 752.5578 1204 2.88E−05 4.12 0.67 3.29 0.59 1.26 753.5674 1204 0.0001 2.95 0.55 2.37 0.43 1.25 755.4866 1204 6.72E−07 3.54 0.37 2.85 0.47 1.24 756.4905 1204 0.0002 2.68 0.34 1.82 1.01 1.47 757.5017 1204 0.0003 3.97 0.42 3.45 0.53 1.15 757.5618 1101 1.53E−06 5.41 0.44 4.65 0.52 1.16 758.5089 1204 0.0007 4.94 0.36 4.53 0.43 1.09 758.5654 1101 1.28E−06 4.37 0.44 3.59 0.54 1.22 759.516 1204 2.72E−05 5.22 0.34 4.67 0.48 1.12 759.578 1101 0.0001 4.15 0.46 3.58 0.45 1.16 760.5223 1204 4.81E−05 4.57 0.3 4.09 0.44 1.12 760.5816 1101 3.36E−05 3.04 0.45 2.44 0.46 1.24 761.5269 1204 2.48E−05 3.16 0.31 2.69 0.39 1.17 765.5665 1201 0.0166 2.93 0.61 2.52 0.53 1.16 766.5701 1201 0.0341 1.88 0.75 1.45 0.6 1.29 767.S821 1201 0.0146 3.46 0.58 3.09 0.41 1.12 768.4944 1204 0.0043 3.82 0.41 3.48 0.39 1.1 768.5507 1202 0.0292 2.46 0.35 2.22 0.42 1.11 769.4957 1204 0.0045 3.02 0.39 2.56 0.65 1.18 770.5109 1204 0.0046 3.21 0.41 2.86 0.42 1.12 771.5809 1204 0.0153 4.35 0.35 4.09 0.36 1.06 772.5269 1204 0.0016 3.71 0.35 3.34 0.43 1.11 772.5856 1204 0.0098 3.34 0.31 3.08 0.35 1.08 773.5337 1204 1.41E−06 3.61 0.28 3.11 0.35 1.16 774.5404 1204 0.0289 2.54 0.61 2.07 0.85 1.23 775.553 1204 0.0039 3.63 0.52 3.19 0.5 1.14 775.5533 1202 0.0031 2.58 0.44 2.11 0.6 1.22 776.5563 1204 0.0039 2.64 0.46 2.09 0.77 1.26 776.6057 1102 0.0029 2.16 0.46 1.62 0.73 1.33 776.6069 1202 0.0388 1.81 0.66 2.13 0.34 0.85 777.5679 1204 0.0026 2.97 0.51 2.57 0.33 1.15 779.5438 1101 5.66E−07 5.11 0.46 4.25 0.59 1.2 779.5831 1204 0.0034 2.62 0.5 2.15 0.56 1.22 780.5474 1101 6.60E−07 4.02 0.47 3.18 0.56 1.27 781.5612 1101 3.67E−07 4.91 0.41 4.11 0.53 1.19 782.5087 1204 0.0001 4.12 0.36 3.58 0.48 1.15 782.5649 1101 2.11E−07 3.83 0.42 3.04 0.49 1.26 783.5141 1204 2.43E−05 3.75 0.31 3.24 0.43 1.16 783.578 1101 1.62E−06 3.95 0.46 3.17 0.54 1.25 783.6349 1204 0.0015 0.13 0.45 0.86 0.99 0.15 784.5235 1204 0.0002 3.77 0.35 3.27 0.52 1.15 784.5813 1101 1.54E−06 2.86 0.45 2.16 0.45 1.33 785.5295 1204 0.0003 3.04 0.36 2.54 0.54 1.2 785.5936 1101 9.67E−06 4.24 0.41 3.57 0.53 1.19 786.5404 1204 2.83E−05 4.19 0.34 3.63 0.49 1.15 786.5967 1101 8.65E−06 3.15 0.38 2.54 0.47 1.24 787.5447 1204 3.19E−05 3.18 0.33 2.67 0.45 1.19 793.5387 1102 1.74E−07 3.64 0.39 2.89 0.47 1.26 794.5126 1204 0.0111 2.51 0.32 1.98 0.95 1.27 794.5424 1102 1.81E−07 2.57 0.33 1.86 0.48 1.38 795.5555 1102 0.0001 2.7 0.44 2.02 0.62 1.34 796.5292 1204 0.0318 3.36 0.34 3.14 0.36 1.07 798.6776 1203 0.0254 1.05 1.09 0.44 0.71 2.39 803.5436 1101 3.89E−07 3.81 0.45 2.87 0.65 1.33 803.5685 1102 3.50E−07 6 0.46 5.19 0.5 1.16 804.547 1101 5.81E−07 2.82 0.43 1.93 0.63 1.46 804.5717 1102 6.08E−07 4.71 0.44 3.97 0.47 1.19 804.7208 1204 0.0112 1.66 1.06 0.89 0.97 1.86 804.7219 1203 0.009 2.47 1.05 1.6 1.19 1.55 805.5606 1101 2.80E−07 4.01 0.45 3.17 0.54 1.27 805.5834 1102 1.15E−05 4.65 0.5 3.98 0.45 1.17 805.7267 1203 0.042 1.47 1.19 0.83 0.97 1.78 806.5643 1101 2.17E−06 3.03 0.47 2.24 0.54 1.35 806.5863 1102 6.89E−06 3.46 0.46 2.78 0.48 1.25 807.5761 1101 4.54E−06 4.24 0.41 3.56 0.51 1.19 808.5795 1101 3.90E−06 3.25 0.4 2.55 0.53 1.27 809.5937 1101 1.58E−05 3.5 0.38 2.92 0.46 1.2 810.5401 1204 0.001 3.52 0.34 3.11 0.46 1.13 810.597 1101 0.0001 2.53 0.42 2.01 0.45 1.26 811.5733 1202 0.0028 3.25 0.52 2.8 0.47 1.16 812.5767 1202 0.0028 2.34 0.47 1.77 0.77 1.33 813.5888 1202 0.0017 3.62 0.45 3.23 0.37 1.12 814.592 1202 0.0008 2.65 0.39 2.26 0.36 1.17 816.5591 1102 3.10E−06 2.26 0.35 1.6 0.51 1.41 816.7297 1204 0.0444 0.25 0.58 0 0 0.25 817.5376 1102 2.59E−07 2.42 0.39 1.6 0.55 1.51 819.5553 1102 0.0001 2.2 0.64 1.32 0.78 1.67 821.5718 1102 2.76E−08 3.02 0.44 2.13 0.5 1.42 822.5751 1102 3.08E−07 2.01 0.44 1.12 0.6 1.79 824.689 1203 0.0032 2.33 0.77 1.53 1.01 1.52 825.5545 1202 0.038 3.16 0.86 2.68 0.67 1.18 825.5548 1102 0.0017 1.06 0.77 0.41 0.55 2.55 826.5579 1202 0.0426 2.12 0.89 1.63 0.75 1.3 826.7053 1203 0.0039 4.43 0.61 3.88 0.66 1.14 827.5439 1101 0.0345 1.82 1.11 1.19 0.88 1.52 827.5698 1102 2.43E−07 4.75 0.39 3.83 0.65 1.24 827.5699 1202 0.0259 6.79 0.5 6.47 0.47 1.05 827.7084 1203 0.0029 3.7 0.6 3.16 0.6 1.17 828.5734 1102 7.16E−08 3.72 0.37 2.87 0.55 1.3 828.5741 1202 0.0258 5.69 0.45 5.4 0.43 1.05 828.7206 1203 0.0268 5.58 0.56 5.22 0.56 1.07 829.5597 1101 0.0052 1.89 0.84 1.19 0.83 1.59 829.5857 1102 2.38E−06 4.41 0.5 3.55 0.61 1.24 829.7239 1204 0.0481 2.77 0.58 2.34 0.86 1.18 829.7244 1203 0.0355 4.83 0.55 4.49 0.55 1.08 830.5887 1102 3.45E−06 3.3 0.5 2.48 0.59 1.33 830.6537 1102 0.0004 2.49 0.35 2.06 0.44 1.21 830.7359 1203 0.0499 5.12 0.61 4.78 0.55 1.07 831.575 1101 0.0001 2.87 0.49 2.31 0.43 1.24 831.575 1101 0.0001 2.87 0.49 2.31 0.43 1.24 831.5999 1102 3.19E−07 5.12 0.51 4.22 0.55 1.22 831.6002 1202 0.0111 6.36 0.46 6.03 0.41 1.06 831.7409 1203 0.0438 4.27 0.6 3.94 0.54 1.09 832.5765 1101 0.0094 0.52 0.87 0.04 0.17 14.81 832.6028 1102 3.72E−07 3.98 0.51 3.1 0.53 1.28 832.6039 1202 0.0119 5.26 0.45 4.95 0.4 1.06 835.6996 1204 0.0102 2.81 0.99 2.01 1.09 1.4 836.7063 1204 0.0067 1.87 1.13 0.98 1.06 1.9 837.5884 1202 0.022 2.81 0.38 2.56 0.37 1.1 837.7182 1204 0.0042 3.32 0.96 2.4 1.17 1.39 838.7227 1204 0.0035 2.64 1.02 1.66 1.19 1.59 839.7321 1204 0.0325 1.64 1.29 0.87 1.13 1.87 847.5955 1202 0.0215 2.67 0.49 2.33 0.49 1.14 850.703 1203 0.0002 3.38 0.6 2.7 0.6 1.25 851.5689 1102 0.0008 2.92 0.63 2.28 0.64 1.28 851.7111 1203 0.0058 3.03 0.57 2.47 0.76 1.22 852.5725 1102 0.0048 1.98 0.68 1.41 0.66 1.4 852.7198 1203 0.0274 5.94 0.62 5.57 0.49 1.07 852.7242 1204 0.0074 3.66 0.62 3.21 0.52 1.14 853.5854 1102 1.66E−5 3.01 0.48 2.33 0.51 1.29 853.7252 1203 0.0376 5.25 0.62 4.91 0.49 1.07 854.5887 1102 0.0004 2.03 0.46 1.43 0.62 1.42 855.6013 1102 9.20E−06 4.14 0.41 3.36 0.66 1.23 856.6046 1102 8.38E−06 3.14 0.41 2.42 0.59 1.3 856.6697 1102 3.72E−07 2.99 0.34 2.28 0.49 1.31 857.617 1102 0.001 2.52 0.8 1.68 0.87 1.5 857.6733 1102 1.09E−06 2.14 0.33 1.34 0.64 1.6 858.6847 1102 2.66E−05 3.48 0.42 2.88 0.49 1.21 859.6877 1102 3.67E−05 2.53 0.4 1.97 0.45 1.28 861.5265 1102 2.01E−06 2.38 0.43 1.63 0.54 1.46 861.7174 1204 0.0161 4.38 0.84 3.81 0.76 1.15 861.7808 1203 0.0128 3.02 0.48 2.66 0.51 1.14 862.7228 1204 0.0046 3.92 0.69 3.34 0.69 1.18 863.6874 1204 0.001 5.36 0.4 4.83 0.63 1.11 863.7339 1204 0.0071 5.83 0.67 5.27 0.72 1.11 864.738 1204 0.0063 5.13 0.63 4.58 0.71 1.12 865.7482 1204 0.0198 5.44 0.75 4.9 0.83 1.11 866.7527 1204 0.0308 4.67 0.78 4.15 0.84 1.13 867.7576 1204 0.0183 3.23 0.75 2.58 1.09 1.25 871.5528 1102 9.31E−07 3.47 0.46 2.69 0.51 1.29 872.5556 1102 1.76E−05 2.41 0.44 1.74 0.54 1.39 873.5684 1102 8.02E−06 2.42 0.51 1.66 0.54 1.45 876.7223 1203 0.0008 4.38 0.59 3.71 0.72 1.18 877.7271 1203 0.0029 3.56 0.64 2.93 0.76 1.22 878.7381 1203 0.0075 6.24 0.6 5.78 0.57 1.08 879.598 1102 0.0007 1.67 0.63 1.1 0.48 1.53 879.742 1203 0.0083 5.51 0.59 5.04 0.59 1.09 880.7528 1203 0.0122 7.31 0.66 6.88 0.46 1.06 880.7555 1204 0.0202 4.51 0.74 4.07 0.5 1.11 881.7568 1203 0.0137 6.55 0.65 6.15 0.43 1.07 881.7609 1204 0.038 4.04 0.8 3.63 0.51 1.11 882.7673 1203 0.0252 7.43 0.71 7.05 0.43 1.06 882.7717 1204 0.0429 4.99 0.81 4.59 0.51 1.09 883.7715 1203 0.0273 6.57 0.69 6.2 0.41 1.06 884.7817 1203 0.0156 6.5 0.7 6.08 0.44 1.07 884.7873 1204 0.0252 4.76 0.76 4.33 0.51 1.1 885.7867 1203 0.0153 5.49 0.66 5.09 0.44 1.08 885.7919 1204 0.0131 4.05 0.73 3.59 0.5 1.13 886.5582 1102 3.88E−07 3.51 0.32 2.75 0.55 1.28 886.8027 1204 0.0165 3.49 0.71 3.05 0.51 1.14 887.5625 1102 3.90E−05 2.6 0.37 1.89 0.67 1.37 887.8022 1203 0.0251 3.28 0.86 2.81 0.48 1.17 893.774 1204 0.0192 5.83 0.8 5.31 0.69 1.1 894.7273 1204 0.001 4.24 0.65 3.6 0.63 1.18 894.7813 1204 0.0049 4.39 0.74 3.78 0.7 1.16 895.5578 1102 2.28E−08 2.61 0.38 1.77 0.5 1.48 895.559 1202 0.0235 2.34 0.41 1.99 0.61 1.17 895.7335 1204 0.0024 3.82 0.67 3.22 0.62 1.18 895.7873 1204 0.0115 2.68 1.32 1.65 1.4 1.62 896.745 1204 0.0031 4.26 0.69 3.69 0.59 1.15 897.573 1102 8.61E−06 2.28 0.49 1.45 0.66 1.57 897.75 1204 0.0053 3.68 0.76 3.13 0.54 1.18 898.7605 1204 0.0026 3.79 0.69 3.22 0.54 1.17 899.5871 1102 6.42E−07 2.93 0.5 2.07 0.54 1.41 899.7663 1204 0.0179 3.04 0.83 2.55 0.53 1.19 900.5897 1102 2.46E−07 1.94 0.46 0.98 0.65 1.98 902.737 1203 0.0022 4.31 0.67 3.71 0.61 1.16 903.7407 1203 0.001 3.66 0.65 2.99 0.68 1.22 904.7535 1203 0.0012 5.52 0.54 5.02 0.48 1.1 905.7573 1203 0.0013 4.79 0.52 4.31 0.45 1.11 906.769 1203 0.0016 5.87 0.48 5.46 0.39 1.08 907.7735 1203 0.0011 5.13 0.47 4.72 0.36 1.09 907.7735 1203 0.0011 5.13 0.47 4.72 0.36 1.09 908.708 1204 0.0018 3.13 0.65 2.43 0.84 1.29 908.7842 1204 0.0092 2.68 0.88 1.92 1.09 1.4 908.7843 1203 0.0011 5.24 0.5 4.78 0.41 1.1 909.7153 1204 0.0151 3.2 0.89 2.64 0.65 1.21 909.7892 1203 0.0011 4.42 0.48 3.99 0.39 1.11 910.7248 1204 0.0047 3.77 0.73 3.2 0.6 1.18 910.7979 1203 0.0001 3.71 0.49 3.12 0.48 1.19 911.7326 1204 0.0069 4.17 0.82 3.57 0.68 1.17 912.7412 1204 0.0105 4.25 0.82 3.69 0.63 1.15 913.7502 1204 0.0143 5.1 0.98 4.49 0.67 1.14 914.7577 1204 0.026 4.9 1.01 4.33 0.67 1.13 915.7673 1204 0.0297 6.06 1.07 5.48 0.68 1.11 916.774 1204 0.0399 5.76 1.03 5.23 0.67 1.1 917.7836 1204 0.0157 6.41 1.05 5.76 0.72 1.11 918.7901 1204 0.0164 5.96 1 5.34 0.7 1.12 919.7981 1204 0.0053 5.38 0.96 4.66 0.75 1.15 920.747 1204 0.0002 4.08 0.58 3.43 0.58 1.19 920.8054 1204 0.0012 4.46 0.91 3.61 0.81 1.23 921.753 1204 0.0011 3.84 0.6 3.13 0.83 1.23 921.8145 1204 0.0021 3.27 1.23 2.07 1.37 1.58 922.7656 1204 0.0003 3.9 0.61 3.24 0.55 1.2 922.8229 1204 0.0198 2.13 1.57 1.14 1.3 1.88 923.5884 1102 4.49E−06 1.95 0.42 1.19 0.59 1.63 923.7675 1204 0.0248 3.35 0.87 2.8 0.78 1.2 924.7826 1204 0.0003 3.34 0.59 2.69 0.58 1.24 926.7371 1203 0.0003 2.14 0.97 1 1.06 2.14 928.7519 1203 0.0006 3.02 0.66 2.31 0.69 1.31 930.7673 1203 0.001 3.37 0.67 2.58 0.89 1.31 931.7691 1203 0.046 2.31 1.18 1.64 1.11 1.41 931.793 1204 0.016 2.05 1.41 1.09 1.26 1.87 932.7819 1203 0.026 3.25 0.79 2.81 0.49 1.15 934.7235 1204 0.0092 3.33 0.88 2.6 1.01 1.28 935.7299 1204 0.0026 3.23 0.59 2.6 0.79 1.24 936.7387 1204 0.0015 3.41 0.59 2.73 0.82 1.25 937.7457 1204 0.0005 3.43 0.61 2.55 1 1.34 938.7553 1204 0.0011 3.6 0.69 2.75 1.01 1.31 939.7616 1204 0.0016 3.39 0.73 2.63 0.84 1.29 940.7709 1204 0.0005 3.65 0.81 2.73 0.92 1.34 941.7779 1204 0.0016 3.31 0.96 2.37 0.99 1.39 942.7876 1204 0.0093 3.5 1.1 2.72 0.89 1.29 943.7931 1204 0.0099 2.93 1.31 1.96 1.2 1.49 944.8033 1204 0.0124 2.95 1.35 1.96 1.3 1.5 945.8085 1204 0.0019 2.54 1.35 1.26 1.38 2.01 946.8187 1204 0.0246 1.89 1.53 0.98 1.21 1.94 950.7385 1203 0.0482 0.54 0.93 0.12 0.4 4.58 952.7568 1203 0.0004 0.91 1.05 0.06 0.3 14.68 952.7759 1204 0.0034 2.34 1.05 1.37 1.16 1.71 954.7905 1204 0.0344 1.44 1.25 0.75 0.95 1.92 962.7616 1204 0.0031 2.2 1.09 1.19 1.17 1.85 964.7764 1204 0.0017 2.64 0.79 1.82 0.93 1.45 965.7839 1204 0.0037 1.95 1.07 1.01 1.08 1.93 966.7933 1204 0.0047 2.48 0.95 1.63 1.07 1.53 967.7981 1204 0.0022 1.91 0.94 0.99 1.05 1.93 968.8072 1204 0.001 1.83 0.91 0.84 1.05 2.17 997.3968 1102 0.0011 2.15 0.22 2.39 0.25 0.9 1016.929 1203 6.70E−06 4.91 0.63 3.87 0.8 1.27 1017.934 1203 3.45E−05 4.56 0.65 3.43 1.04 1.33 1018.943 1203 3.17E−05 4.22 0.7 3.11 0.96 1.35 1019.95 1203 9.64E−06 3.37 0.7 2.07 1.1 1.63 1040.934 1203 0.0011 2.27 1.16 1.13 1.12 2 1176.777 1204 0.0452 4.32 1.09 4.92 0.96 0.88 1225.093 1203 0.0048 3.34 0.82 2.59 0.96 1.29 1226.098 1203 0.0077 3.11 0.94 2.49 0.55 1.25 1227.107 1203 0.0202 3.47 0.95 2.81 0.98 1.23 1228.113 1203 0.0104 3.07 0.88 2.5 0.59 1.23 1229.118 1203 0.0018 2.11 0.93 1.12 1.16 1.89 1251.115 1203 0.0026 1.62 1.24 0.62 0.93 2.6 1253.129 1203 0.0043 1.91 1.21 0.96 0.99 2 1373.744 1201 0.0039 0.2 0.55 0.89 0.98 0.22

TABLE 2 Accurate masses, putative molecular formulae and proposed structures for the seven prostrate cancer biomarkers detected in aqueous extracts (positive chemical ionization) of human serum. Metabolite Detected ID Mass Exact Mass Formula Proposed Structure 1 495.3328 495.3325 C₂₄H₅₀NO₇P

2 517.3147 517.3168 C₂₆H₄₈NO₇P

3 519.3328 519.3325 C₂₆H₅₀NO₇P

4 521.3481 521.3481 C₂₆H₅₂NO₇P

5 523.3640 523.3638 C₂₆H₅₄NO₇P

6 541.3148 541.3168 C₂₈H₄₈NO₇P

7 545.3460 545.3481 C₂₈H₅₂NO₇P

TABLE 3 MS/MS fragmentation of prostate cancer biomarker 495.3328, C₂₄H₅₀NO₇P (m/z represents the [M + H]⁺ mass) Fragment m/z Formula Molecular fragment loss 496 C₂₄H₅₁NO₇P⁺

478 C₂₄H₄₉NO₆P⁺

496 − H₂O 419 C₂₁H₄₀NO₆P⁺

313 C₁₉H₃₇O₃ ⁺

478 − 166 + H⁺ 283 C₁₇H₃₁O₃ ⁺

313 − C₂H₆ 258 C₈H₂₁NO₇P⁺

496 − C₁₆H₃₀O 239 C₁₆H₃₁O

496 − C₈H₂₀NO₅P 184 C₅H₁₅NO₄P⁺

166 C₅H₁₃NO₃P⁺

478 − 313 104 C₅H₁₄NO

184 − HPO₃ 86 C₆H₁₂N

104 − H₂O

TABLE 4 MS/MS fragmentation of prostate cancer biomarker 517.3147, C₂₆H₄₈NO₇P (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment Fragment loss 518 C₂₆H₄₉NO₇P⁺

459 C₂₃H₄₀NO₇P⁺

415 C₂₁H₃₆O₆P⁺

459 − C₂H₄O 359 C₁₇H₂₈O₆P⁺

415 − C₄H₈ 341 C₁₇H₂₆O₅P⁺

359 − H₂O 281 C₁₀H₁₈NO₇P⁺

459 − C₁₃H₂₂ 221 C₈H₁₄NO₅P⁺

359 − C₉H₁₄ 104 C₅H₁₄NO

 86 C₅H₁₂N

104 − H₂O

TABLE 5 MS/MS fragmentation of prostate cancer biomarker 519.3328, C₂₆H₅₂NO₇P (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment 520 C₂₆H₅₁NO₇P⁺

502 C₂₆H₄₉NO₆P⁺

461 C₂₃H₄₂NO₇P⁺

445 C₂₂H₃₈NO₇P⁺

281 C₁₈H₃₃O₂

221 C₁₆H₂₉

184 C₅H₁₅NO₄P⁺

166 C₅H₁₃NO₃P⁺

124 C₂H₆O₄P⁺

 86 C₅H₁₂N

m/z Fragment loss 520 502 520 − H₂O 461

445 461 − CH₄ 281 520 − C₈H₂₀NO₅P 221

184 166 184 − H₂O 124

 86 166 − H₃PO₄

TABLE 6 MS/MS fragmentation of prostate cancer biomarker 521.3481, C₂₆H₅₃NO₇P⁺ (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment Fragment loss 522 C₂₆H₅₃NO₇P⁺

504 C₂₆H₅₁NO₆P⁺

522 − H₂O 478 C₂₃H₄₅NO₇P⁺

522 − C₃H₈ 357 C₁₈H₃₀NO₅P⁺

258 C₈H₂₁NO₆P⁺

C₁₈H₃₃O⁺ 221 C₁₅H₂₅O⁺

C₁₈H₃₃O⁺ − C₃H₈ 184 C₅H₁₅NO₄P⁺

522 − C₂₁H₃₈O₃ 124 C₂H₆O₄P⁺

104 C₅H₁₄NO

184 − HPO₃  86 C₅H₁₂N

104 − H₂O

TABLE 7 MS/MS fragmentation of prostate cancer biomarker 523.3640, C₂₆H₅₅NO₇P⁺ (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment Fragment loss 524 C₂₆H₅₅NO₇P⁺

506 C₂₆H₅₃NO₆P⁺

524 − H₂O 496 C₂₄H₅₁NO₇P⁺

524 − C₂H₄ 478 C₂₄H₄₉NO₆P⁺

496 − H₂O 331 C₁₉H₃₉O₄ ⁺

496 − 166 + H⁺ 313 C₁₉H₃₇O₃ ⁺

258 C₈H₂₁NO₆P⁺

524 − C₁₈H₃₄O 285 C₁₈H₃₇O₃ ⁺

524 − C₈H₂₀NO₅P 184 C₅H₁₅NO₄P⁺

524 − 313 166 C₅H₁₃NO₃P⁺

184 − H₂O 124 C₂H₆O₄P⁺

104 C₅H₁₄NO

184 − HPO₃  86 C₅H₁₂N

104 − H₂O

TABLE 8 MS/MS fragmentation of prostate cancer biomarker 541.3148, C₂₈49₅NO₇P⁺ (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment Fragment loss 542 C₂₈H₄₉NO₇P⁺

483 C₂₅H₄₀NO₇P⁺

284 C₉H₁₉NO₇P⁺

542 − C₁₉H₃₀ 255 C₆H₁₀NO₇P⁺

483 − C₁₉H₃₀ 184 C₅H₁₅NO₄P⁺

542 − C₂₃H₃₄O₃ 104 C₅H₁₄NO

184 − HPO₃  86 C₅H₁₂N

104 − H₂O

TABLE 9 MS/MS fragmentation of prostate cancer biomarker 545.3460, C₂₈H₅₃NO₇P⁺ (m/z represents the [M + H]⁺ mass) m/z Formula Molecular fragment Fragment loss 546 C₂₈H₅₃NO₇P⁺

528 C₂₈H₅₁NO₆P⁺

546 − H₂O 514 C₂₇H₄₉NO₆P⁺

528 − CH₃ 487 C₂₅H₄₄NO₇P⁺

104 C₅H₁₄NO

 86 C₅H₁₂N

104 − H₂O

TABLE 10 Comparison of fragment ion patterns for 2-Hydroxy-1- palmitoyl-sn-glycero-3-phosphocholine and 495.3328. Standard 495.3328 Fragment Ion [M + H] % 496 100 90 478 1 5 419 1 1 313 10 1 239 1 1 258 1 1 184 80 90 166 1 1 104 30 100 86 1 70

TABLE 11 Accurate masses, putative molecular formulae and proposed structures for the seven prostate cancer biomarkers detected in aqueous extracts (negative electrospray ionization) of human serum. Detected Calculated Mass Mass Formula Proposed Structure 481.317 481.3168 C₂₃H₄₈NO₇P

531.3123 531.3114 C₃₀H₄₆NO₅P 541.3422 541.3380 C₂₅H₅₂NO₉P

555.3101 555.3172 C₂₅H₅₀NO₁₀P

565.3394 565.3380 C₂₇H₅₂NO₉P

567.3546 567.3536 C₂₇H₅₄NO₉P

569.3687 569.3693 C₂₇H₅₆NO₉P

TABLE 12 MS/MS fragmentation of prostate cancer biomarker 481.3171, C₂₃H₄₈NO₇P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 480 C₂₃H₄₇NO₇P

−H⁺ 462 C₂₃H₄₅NO₆P

−H₂O 435 C₂₁H₄₀O₇P

480 − NH(CH₃)₂ 391 C₁₉H₃₆NO₆P

255 C₁₆H₃₁O₂

242 C₆H₁₃NO₇P

224 C₆H₁₁NO₆P

242 − H₂O 168 C₄H₁₁NO₄P

153 C₃H₆O₅P

 79 PO₃

TABLE 13 MS/MS fragmentation of prostate cancer biomarker 531.3123, C₃₀H₄₆NO₅P (m/z represents the [M − H]⁻ mass) m/z Formula 530 C₃₀H₄₅NO₅P 480 255 224 168 78

TABLE 14 MS/MS fragmentation of prostate cancer biomarker 541.3380, C₂₅H₅₂NO₉P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 540 C₂₅H₅₁NO₉P

−H⁺ 480 C₂₃H₄₇NO₇P

255 C₁₆H₃₁O₂

242 C₇H₁₇NO₆P

224 C₇H₁₅NO₅P

242 − H₂O 168 C₄H₁₁NO₄P

153 C₃H₆O₅P

 79 PO₃

TABLE 15 MS/MS fragmentation of prostate cancer biomarker 555.3172, C₂₆H₅₄NO₉P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 554 C₂₆H₅₃NO₉P

−H⁺ 508 C₂₅H₅₂NO₇P

−HCOOH 494 C₂₃H₄₅NO₈P

463 C₂₂H₄₀O₈P

494 − CH₃NH₂ 281 269 C₁₇H₃₂O₂

242 C₇H₁₇NO₆P 224 C₆H₁₁NO₆P

168 153  79

TABLE 16 MS/MS fragmentation of prostate cancer biomarker 565.3394, C₂₇H₅₂NO₉P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 564 C₂₇H₅₁NO₉P

−H⁺ 504 C₂₅H₄₅NO₈P

454 C₁₉H₃₇NO₉P

279 C₁₈H₃₁O₂

242 C₇H₁₇NO₆P

224 C₇H₁₅NO₅P

242 − H₂O 168 C₄H₁₁NO₄P

153 C₃H₆O₅P

 79 PO₃

TABLE 17 MS/MS fragmentation of prostate cancer biomarker 567.3546, C₂₇H₅₄NO₉P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 566 C₂₇H₅₃NO₉P

−H⁺ 506 C₂₅H₄₇NO₈P

281 C₁₈H₃₃O₂

242 C₇H₁₇NO₆P

224 C₇H₁₅NO₅P

242 − H₂O 168 C₄H₁₁NO₄P

153 C₃H₆O₅P

 79 PO₃

TABLE 18 MS/MS fragmentation of prostate cancer biomarker 569.368, C₂₇H₅₆NO₉P (m/z represents the [M − H]⁻ mass) m/z Formula Molecular fragment Fragment loss 568 C₂₇H₅₅NO₉P

−H⁺ 508 C₂₅H₄₉NO₈P

283 C₁₈H₃₅O₂

242 C₇H₁₇NO₆P

224 C₇H₁₅NO₅P

242 − H₂O 168 C₄H₁₁NO₄P

153 C₃H₆O₅P

 79 PO₃

TABLE 19 Comparison of MS/MS fragmentation patterns of 569.3687 to it's corresponding lysophospholipid ethanolamine counterpart, 2-hydroxy-1-stearyl-sn-glycero-3-phosphoethanolamine standard. Standard 569.3687 m/z Molecular fragment m/z Molecular fragment where R = 60 D 568

480

508 (568 − 60)

283

283

214

242

196

224

140

168

153

153

 79

 79

TABLE 20 Daughter Daughter Daughter Daughter Daughter Parent 1 2 3 4 5 PESI 496.33 184.2 104.2 313.4 419.4 86.2 518.31 104.2 459.4 313.4 415.5 147.1 520.33 184.2 104.2 337.4 166.2 86.2 522.35 184.2 104.2 339.4 258.4 445.3 524.36 184.2 104.2 341.4 258.2 86.2 542.31 104.2 483.4 337.4 439.4 359.4 546.35 487.4 104.2 341.4 443.5 147.0 IS 609.30 195.2 397.3 NESI 480.32 255.4 224.2 242.2 283.4 153.0 530.31 480.5 255.4 305.4 326.2 484.3 540.34 480.5 255.4 224.2 242.2 153.0 554.31 494.5 269.4 283.4 508.2 224.2 564.34 504.5 279.4 224.2 242.2 415.3 566.35 506.5 281.4 224.2 242.2 153.0 568.37 508.5 283.4 224.2 242.2 419.5 IS 607.20 211.3 152.2 *Note: The parent m/z and the 2 daughter MRM transitions used in each method are in bold. Additional daughter transitions listed could also be used in other methods in the future. 

What is claimed is:
 1. A method for determining a change in prostate cancer in a patient, the method comprising the steps of: a) analyzing at least one blood sample from said patient by high resolution mass spectrometry to obtain accurate mass intensity data; b) comparing the accurate mass intensity data to corresponding data obtained from one or more than one reference blood sample to identify an increase or decrease in accurate mass intensity; and c) using said increase or decrease in accurate mass intensity to determine change in prostate cancer in said patient, wherein the accurate mass intensity is measured at one or more of the following hydrogen and electron adjusted accurate masses or neutral accurate masses, in Daltons, ±5 ppm, wherein the hydrogen and electron adjusted accurate masses or neutral accurate masses at which intensity decreases are: 174.1408, 188.1566, 194.0804, 232.9133, 242.2251, 252.2096, 258.2482, 268.2412, 272.2357, 276.2096, 278.2256, 279.2287, 280.2414, 281.2448, 283.2602, 292.204, 296.2358, 298.2519, 299.2558, 300.2098, 300.2676, 302.2256, 304.2394, 304.241, 305.243, 305.2439, 306.257, 308.2715, 310.2154, 310.2884, 312.2313, 312.304, 314.2464, 320.2358, 326.2262, 327.0326, 329.2426, 329.2445, 330.2568, 340.2977, 342.2198, 368.3437, 369.3474, 371.3538, 392.294, 411.3186, 430.3083, 430.3818, 431.3861, 432.3686, 452.2536, 481.3171, 481.3172, 482.3216, 484.3792, 492.4184, 494.4344, 495.3328, 495.4376, 496.336, 501.2848, 505.3227, 506.3213, 507.3317, 509.3493, 517.3148, 518.3182, 518.4345, 519.332, 519.3328, 520.4502, 521.348, 521.4526, 522.464, 523.364, 523.4678, 524.4725, 529.3167, 531.3123, 534.4645, 538.501, 541.3148, 541.3422, 541.3433, 542.3453, 542.3461, 545.346, 548.4817, 549.4848, 552.4048, 555.3101, 565.3393, 565.3394, 566.3433, 566.3434, 567.3546, 567.3548, 568.3573, 568.3574, 569.3687, 569.3691, 570.3726, 570.4653, 570.4915, 579.5322, 580.5345, 587.3228, 589.3401, 589.3404, 590.343, 590.4597, 596.4794, 599.4932, 601.5077, 604.5441, 605.5469, 609.3242, 612.5004, 615.4797, 622.4973, 623.4918, 623.5003, 624.5134, 625.5078, 625.5163, 626.5109, 626.5285, 627.5204, 627.5306, 628.5236, 628.5426, 629.5453, 630.5582, 632.5752, 635.5246, 641.4915, 646.5709, 647.574, 647.6063, 648.5865, 649.5056, 649.5898, 655.5509, 660.5005, 660.6082, 663.4864, 670.5688, 670.5711, 671.5723, 672.5865, 673.5893, 673.6185, 673.6224, 675.6359, 675.6375, 676.6393, 680.5625, 684.5487, 685.5543, 686.5126, 688.5294, 690.4849, 690.547, 692.5571, 693.611, 695.647, 696.5856, 696.651, 699.5205, 702.5675, 705.6083, 707.6256, 708.6308, 710.4923, 716.4982, 721.6388, 722.6423, 723.5194, 723.5198, 724.5247, 724.5496, 725.5375, 726.5456, 727.5565, 728.562, 729.5724, 731.4913, 732.4938, 733.6425, 735.6555, 736.6584, 737.5354, 738.5449, 741.5307, 742.5354, 743.5469, 744.4942, 745.4972, 746.556, 747.5201, 747.5234, 748.5279, 748.5722, 749.5346, 749.5354, 749.5364, 749.5402, 749.5763, 750.5403, 750.5434, 751.551, 751.5529, 751.5548, 752.5565, 752.5578, 753.5674, 755.4866, 756.4905, 757.5017, 757.5618, 758.5089, 758.5654, 759.516, 759.578, 760.5223, 760.5816, 761.5269, 765.5665, 766.5701, 767.5821, 768.4944, 768.5507, 769.4957, 770.5109, 771.5809, 772.5269, 772.5856, 773.5337, 774.5404, 775.553, 775.5533, 776.5563, 776.6057, 777.5679, 779.5438, 779.5831, 780.5474, 781.5612, 782.5087, 782.5649, 783.5141, 783.578, 784.5235, 784.5813, 785.5295, 785.5936, 786.5404, 786.5967, 787.5447, 793.5387, 794.5126, 794.5424, 795.5555, 796.5292, 798.6776, 803.5436, 803.5685, 804.547, 804.5717, 804.7208, 804.7219, 805.5606, 805.5834, 805.7267, 806.5643, 806.5863, 807.5761, 808.5795, 809.5937, 810.5401, 810.597, 811.5733, 812.5767, 813.5888, 814.592, 816.5591, 816.7297, 817.5376, 819.5553, 821.5718, 822.5751, 824.689, 825.5545, 825.5548, 826.5579, 826.7053, 827.5439, 827.5698, 827.5699, 827.7084, 828.5734, 828.5741, 828.7206, 829.5597, 829.5857, 829.7239, 829.7244, 830.5887, 830.6537, 830.7359, 831.575, 831.5999, 831.6002, 831.7409, 832.5765, 832.6028, 832.6039, 835.6996, 836.7063, 837.5884, 837.7182, 838.7227, 839.7321, 847.5955, 850.703, 851.5689, 851.7111, 852.5725, 852.7198, 852.7242, 853.5854, 853.7252, 854.5887, 855.6013, 856.6046, 856.6697, 857.617, 857.6733, 858.6847, 859.6877, 861.5265, 861.7174, 861.7808, 862.7228, 863.6874, 863.7339, 864.738, 865.7482, 866.7527, 867.7576, 871.5528, 872.5556, 873.5684, 876.7223, 877.7271, 878.7381, 879.598, 879.742, 880.7528, 880.7555, 881.7568, 881.7609, 882.7673, 882.7717, 883.7715, 884.7817, 884.7873, 885.7867, 885.7919, 886.5582, 886.8027, 887.5625, 887.8022, 893.774, 894.7273, 894.7813, 895.5578, 895.559, 895.7335, 895.7873, 896.745, 897.573, 897.75, 898.7605, 899.5871, 899.7663, 900.5897, 902.737, 903.7407, 904.7535, 905.7573, 906.769, 907.7735, 908.708, 908.7842, 908.7843, 909.7153, 909.7892, 910.7248, 910.7979, 911.7326, 912.7412, 913.7502, 914.7577, 915.7673, 916.774, 917.7836, 918.7901, 919.7981, 920.747, 920.8054, 921.753, 921.8145, 922.7656, 922.8229, 923.5884, 923.7675, 924.7826, 926.7371, 928.7519, 930.7673, 931.7691, 931.793, 932.7819, 934.7235, 935.7299, 936.7387, 937.7457, 938.7553, 939.7616, 940.7709, 941.7779, 942.7876, 943.7931, 944.8033, 945.8085, 946.8187, 950.7385, 952.7568, 952.7759, 954.7905, 962.7616, 964.7764, 965.7839, 966.7933, 967.7981, 968.8072, 1016.929, 1017.934, 1018.943, 1019.95, 1040.934, 1225.093, 1226.098, 1227.107, 1228.113, 1229.118, 1251.115, and 1253.129, and a decrease in the accurate mass intensity at one or more of said accurate masses in the blood sample from the patient relative to the reference indicates that the patient has prostate cancer or is at risk of prostate cancer; and wherein the hydrogen and electron adjusted accurate masses or neutral accurate masses at which intensity increases are: 202.0454, 205.8867, 216.0401, 218.0372, 226.0687, 228.1476, 243.0719, 244.056, 247.9578, 273.874, 283.9028, 317.9626, 326.2476, 328.2628, 331.8326, 339.9964, 341.8614, 351.8906, 354.1668, 382.2903, 472.3925, 473.3957, 552.3825, 582.2469, 583.2504, 736.2234, 776.6069, 783.6349, 997.3968, 1176.777 and 1373.744, and an increase in the accurate mass intensity at one or more of said accurate masses in the blood sample from the patient relative to the reference indicates that the patient has prostate cancer or is at risk of prostate cancer.
 2. The method of claim 1, wherein the accurate mass intensities represent ionized metabolites.
 3. The method of claim 1, further comprising analyzing at least one sample from said patient by mass spectrometry to obtain accurate mass intensity data for one or more than one internal control metabolite; and calculating a ratio for each of the accurate mass intensities obtained in step (a) to the accurate mass intensities obtained for the one or more than one internal control metabolite; wherein the comparing step (b) comprises comparing each ratio to one or more corresponding ratios obtained for one or more than one reference sample.
 4. The method of claim 1, wherein the hydrogen and electron adjusted accurate mass, or neutral accurate mass, is selected from the group consisting of: a) 495.3328, b) 517.3148, c) 519.3328, d) 521.3480, e) 523.3640, f) 541.3148, g) 545.3460, h) 481.3171, i) 531.3123, j) 541.3422, k) 555.3101, l) 565.3394, m) 567.3546, n) 569.3687 and combinations thereof, and a decrease in accurate mass intensity at one or more of said accurate masses in the blood sample from the patient relative to the reference indicates that the patient has prostate cancer or is at risk of prostate cancer.
 5. The method of claim 1, wherein the accurate mass intensity data is obtained using a Fourier transform ion cyclotron resonance, time of flight, orbitrap, quadrupole or triple quadrupole mass spectrometer.
 6. The method of claim 1, wherein the blood sample is a whole blood sample, a blood serum sample, or a plasma sample.
 7. The method of claim 1, wherein a liquid/liquid extraction is performed on the blood samples whereby non-polar metabolites are dissolved in an organic solvent and polar metabolites are dissolved in an aqueous solvent.
 8. The method of claim 1, wherein said one or more than one reference blood sample is a plurality of blood samples obtained from control individuals; one or more than one baseline sample obtained from the patient at an earlier date; or a combination thereof.
 9. A method for determining prostate cancer, a change in prostate cancer, or the risk of prostate cancer in a patient, the method comprising the steps of: a) analyzing at least one blood sample from said patient to obtain quantifying data for one or more than one metabolite marker using an analytical device or system; b) comparing the quantifying data for said one or more than one metabolite marker to corresponding data obtained for one or more than one reference blood sample to identify a decrease in the level of said one or more than one metabolite marker in said blood sample; and c) using said decrease in the level of said one or more than one metabolite marker in said at least one sample for determining prostate cancer, change in prostate cancer, or the risk of prostate cancer in said patient, wherein the one or more than one metabolite marker comprises one or more lysophospholipid selected from the group consisting of: lysophosphatidylcholines, lysophosphatidylethanolamines, lysophosphatidyldimethylethanolamines, lysophosphatidylserines, lysosphingosylphosphoryl-cholines, lysophosphatidylglycerols, lysophosphatidylinositols, platelet activating factors (PAFs), and combinations thereof, and wherein a decrease in the level of said one or more than one metabolite marker in the blood sample from the patient relative to the reference indicates that patient has prostate cancer or is at risk of prostate cancer.
 10. The method of claim 9, wherein step a) comprises analyzing the blood sample by liquid chromatography mass spectrometer (LC-MS).
 11. The method of claim 9, wherein the method is a high-throughput method and step a) comprises analyzing the blood sample by direct injection or liquid chromatography and linear ion trap tandem mass spectrometry.
 12. The method of claim 9, further comprising: analyzing at least one sample from said patient to obtain quantifying data for one or more than one internal control metabolite; and obtaining a ratio for each of the levels of said one or more than one metabolite marker to the level obtained for the one or more than one internal control metabolite; wherein the comparing step (b) comprises comparing each ratio to one or more corresponding ratios obtained for the one or more than one reference sample.
 13. The method of claim 9, wherein said one or more than one reference blood sample is a plurality of blood samples obtained from control individuals; one or more than one baseline blood sample obtained from the patient at an earlier date; or a combination thereof.
 14. The method of claim 9, wherein said lysophospholipids are lysophosphatidylcholine-related compounds.
 15. The method of claim 9, wherein said lysophospholipids are N,N-dimethyl-lysophosphoethanolamine-related compounds.
 16. The method of claim 14, wherein the one or more than one metabolite is characterized by a) at least one MS/MS transition detected in [M+H]+ mode selected from 496, 478, 419, 313, 283, 258, 239, 184, 166, 104, or 86 for molecular formula C24H51NO7P+; b) at least one MS/MS transition detected in [M+H]+ mode selected from 518, 459, 415, 359, 341, 281, 221, 104, or 86 for molecular formula C26H49NO7P+; c) at least one MS/MS transition detected in [M+H]+ mode selected from 520, 502, 461, 445, 281, 221, 184, 166, 124, or 86 for molecular formula C26H51NO7P+; d) at least one MS/MS transition detected in [M+H]+ mode selected from 522, 504, 478, 357, 258, 221, 184, 124, 104 or 86 for molecular formula C26H53NO7P+; e) at least one MS/MS transition detected in [M+H]+ mode selected from 524, 506, 496, 478, 331, 313, 258, 285, 184, 166, 124, 104 or 86 for molecular formula C26H55NO7P+; f) at least one MS/MS transition detected in [M+H]+ mode selected from 542, 483, 284, 225, 184, 104, or 86 for molecular formula C28H49NO7P+; or g) at least one MS/MS transition detected in [M+H]+ mode selected from 546, 528, 514, 487, 104, or 86 for molecular formula C28H53NO7P+.
 17. The method of claim 15, wherein the one or more than one metabolite is characterized by: j) at least one MS/MS transition detected in [M−H]− mode selected from 540, 480, 255, 242, 224, 168, 153 or 79 for molecular formula C25H51NO9P−; l) at least one MS/MS transition detected in [M−H]− mode selected from 564, 504, 454, 279, 242, 224, 168, 153, or 79 for molecular formula C27H51NO9P−; m) at least one MS/MS transition detected in [M−H]− mode selected from 566, 506, 281, 242, 224, 168, 153, or 79 for molecular formula C27H53NO9P−; or n) at least one MS/MS transition detected in [M−H]− mode selected from 568, 508, 283, 242, 224, 168, 153 or 79 for molecular formula C27H55NO9P−.
 18. The method of claim 9, wherein the one or more than one metabolite is characterized by the structure


19. The method of claim 9, wherein the quantifying data is obtained using a Fourier transform ion cyclotron resonance, time of flight, orbitrap, quadrupole or triple quadrupole mass spectrometer.
 20. The method of claim 19, wherein the mass spectrometer is equipped with a chromatographic system.
 21. The method of claim 20, wherein the chromatographic system is a liquid or gas chromatographic system.
 22. The method of claim 9, wherein the blood sample is a whole blood sample, a blood serum sample, or a blood plasma sample.
 23. The method of claim 9, wherein a liquid/liquid extraction is performed on the blood samples whereby non-polar metabolites are dissolved in an organic solvent and polar metabolites are dissolved in an aqueous solvent.
 24. The method of claim 23, wherein the extracted samples are analyzed by positive or negative electrospray ionization, positive or negative atmospheric pressure chemical ionization, or a combination thereof.
 25. The method of claim 1, wherein the accurate mass intensity is measured at the hydrogen and electron adjusted accurate mass or neutral accurate mass, in Daltons, ±1 ppm.
 26. The method of claim 9, wherein the decrease in the level of said one or more than one metabolite marker in said sample is identified in the comparing step (b) using a colorimetric chemical assay, an antibody-based enzyme-linked immunosorbant assay (ELISA), a dipstick chemical assay, or a mass spectrometry-based system.
 27. The method of claim 9, wherein the method is for determining prostate cancer in a patient.
 28. The method of claim 9, wherein the method is for determining a change in prostate cancer in a patient.
 29. The method of claim 9, wherein the method is for determining the risk of prostate cancer in a patient.
 30. A method for determining a change in prostate cancer in a patient, the method comprising the steps of: a) analyzing at least one blood sample from said patient by high resolution mass spectrometry to obtain accurate mass intensity data; b) comparing the accurate mass intensity data to corresponding data obtained from one or more than one reference blood sample to identify an increase or decrease in accurate mass intensity; and c) using said increase or decrease in accurate mass intensity to determine a change in prostate cancer in said patient, wherein the accurate mass intensity is measured at a hydrogen and electron adjusted accurate mass or neutral accurate mass of 519.3328, in Daltons, ±5 ppm and wherein a decrease in the accurate mass intensity of 519.3328 in the blood sample from the patient relative to a reference blood sample indicates that patient has prostate cancer or is at risk of prostate cancer. 